Bang on

You are right, the losing runs can be long but in the long run there is an additional edge of 10 - 20% by using L15s.
Most of my betting is on the exchanges and I too increase my stakes when my total profit reaches a new high on a weekly basis.
I started at £10 per day and I'm now up to over £100 per day.

Each to their own, regular steady progress is reliable IMO, that's why I stick to singles ( with a rare double etc). The point I was making, was that it is a long time between drinks waiting for a 'lucky 15', and taking away the 1 successful bet would show the overall betting ( and selection process) in a truer light. I tend to use a 'Ratchet bank', meaning that I ratchet up after the bank increases, BUT, never reduce stakes after losers. The gradual increase is similar to compounding and the gradual increase in stakes starts to accelerate profits. For me personally, this gives much better returns in the long run.

If you hadn't had the 1 'Lucky 15' (the clue is in the name), what would your YTD be ? You are again changing trying to win people over, rather than just trying to win.
There will always be bad days, bad weeks, and occasionally a bad (or seemingly pointless) months. You have to do your own thing, the fact that the bookies least favourite ( and least profitable) bet is the single should tell you something. There is a lot of racing these days (too much in reality), but as a punter, we don't have to bet in every race, or even every day. 

An interesting sprint at Musselburgh, with 2 lively contenders both dropping down the weights.
7.50 Muss -
Primo's Comet - 4/1 generally - Is now 13lbs below his winning mark (within the last year), is a 6 x CD winner, and the Mulrennan/Goldie (19% when paired) combination.
Latin Five - 7/2 with W.Hills - Is now 10lbs below his winning mark (within the last year), is a 3 x D winner (but not course), and the Lee/Midgley (20% when paired) combination.
I have backed both, and will be keeping an eye on (via tracker) whoever doesn't win as they are sure to be winning soon.

An interesting sprint at Musselburgh, with 2 lively contenders both dropping down the weights.
7.50 Muss -
Primo's Comet - 4/1 generally - Is now 13lbs below his winning mark (within the last year), is a 6 x CD winner, and the Mulrennan/Goldie (19% when paired) combination.
Latin Five - 7/2 with W.Hills - Is now 10lbs below his winning mark (within the last year), is a 3 x D winner (but not course), and the Lee/Midgley (20% when paired) combination.
I have backed both, and will be keeping an eye on (via tracker) whoever doesn't win as they are sure to be winning soon.

2.30 - Chindit - 11/1
3.40 - Dramatised - 5/1
5.00 - Law of the Sea - 13/2
6.10 - Raymond Tusk - 33/1
Each Way 365

2.30 - Chindit - 11/1
3.40 - Dramatised - 5/1
5.00 - Law of the Sea - 13/2
6.10 - Raymond Tusk - 33/1
Each Way 365

2.30 - Chindit - 11/1
3.40 - Dramatised - 5/1
5.00 - Law of the Sea - 13/2
6.10 - Raymond Tusk - 33/1
Each Way 365

I read that it made mistakes in its LTO race at the same venue and that put me off.  The same writer recommended Gina Force Ew.  We all know what happened there.  Great result with Mighty Gurkha though

Dancingontheedge - lost disappointing
Mighty Gurkha - WON comfortably

Dancingontheedge - lost disappointing
Mighty Gurkha - WON comfortably

Dancingontheedge - lost disappointing
Mighty Gurkha - WON comfortably

6.40 Uttox - Dancingontheedge - 2/1 - From my tracker, for me this P.Nicholls runner hasn't really been busy, ridden at the back and taking the scenic route (extra furlong). Cheekpieces are added today and Harry Cobden takes the ride after others rode the last couple of runs. The only Nicholls runner at the course today where he has a 20% strike rate.
7.55 Leic - Mighty Gurkha - 5/1 EW ( with bet365 as they are paying 1/5 3 places in a 7 runner race). Is falling down the weights (13lbs in last 6 runs), and is starting to look well handicapped. Jockey Taylor Fisher takes off a further 5lbs making it a very attractive bet at 5/1 with 3 places.

RESULTS UPDATE
At long last I am in a YTD profit.  One of my L15's and accas won with three winning selections and a non-runner.  This produced a profit of 189.53 points + a small return on an ew bet meant a profit for the day of 190.23.  After deducting my YTD loss of -133.92 I am now in YTD profit of 56.31

3.40 Newton Abbot Magic Saint 9/2
Decent class 2 race with 2-3 improvers. Light N Strike and Clear The Runway need to prove they can win off their current marks with the former recording a very good time last time out . The selection though is Paul Nichols Magic Saint who’s absolutely thrown in here running in it’s first handicap since earlier in the year last handicap mark 143 now 127. He’s been running in hunter chases for a bit now without pulling up too many trees but this is not as hot as the handicaps he was once used to .Not as good as once was but as I’ve said he really is thrown in and has a good claiming jockey on board to aid the cause a bit more.  Interesting race. 
 
5 points win 

finished 3rd, beaten about a length.

finished 3rd, beaten about a length.

7.00 Ayr - Tilsitt  - 7/2 with bet365 (also paying 3 places in a 7 runner race) - likes it at Ayr with 3 wins at the course ( 2 x CD ). In fact his last 3 wins have all been here. Went from the front last time but weakened in the last furlong.  Has been dropped a further 2lbs and Joe Fanning ( Fanning from the front) takes the ride (2nd top course jockey riding here today). I'm on for WIN, but with bet365 offering 3 places(extra place offer) in a 7 runner race, it may appeal to others.

7.00 Ayr - Tilsitt  - 7/2 with bet365 (also paying 3 places in a 7 runner race) - likes it at Ayr with 3 wins at the course ( 2 x CD ). In fact his last 3 wins have all been here. Went from the front last time but weakened in the last furlong.  Has been dropped a further 2lbs and Joe Fanning ( Fanning from the front) takes the ride (2nd top course jockey riding here today). I'm on for WIN, but with bet365 offering 3 places(extra place offer) in a 7 runner race, it may appeal to others.

You seem to be changing your approach again. Your tag at the bottom says .. In handicap races we are not looking for long shots .
 

7.00 Ayr - Tilsitt  - 7/2 with bet365 (also paying 3 places in a 7 runner race) - likes it at Ayr with 3 wins at the course ( 2 x CD ). In fact his last 3 wins have all been here. Went from the front last time but weakened in the last furlong.  Has been dropped a further 2lbs and Joe Fanning ( Fanning from the front) takes the ride (2nd top course jockey riding here today). I'm on for WIN, but with bet365 offering 3 places(extra place offer) in a 7 runner race, it may appeal to others.

7.00 Ayr - Tilsitt  - 7/2 with bet365 (also paying 3 places in a 7 runner race) - likes it at Ayr with 3 wins at the course ( 2 x CD ). In fact his last 3 wins have all been here. Went from the front last time but weakened in the last furlong.  Has been dropped a further 2lbs and Joe Fanning ( Fanning from the front) takes the ride (2nd top course jockey riding here today). I'm on for WIN, but with bet365 offering 3 places(extra place offer) in a 7 runner race, it may appeal to others.

You seem to be changing your approach again. Your tag at the bottom says .. In handicap races we are not looking for long shots .
 

I think you need to change your approach, you jump from track to track (much better to focus on 1 or 2 tracks as you get to know the dogs and trainers). Also backing 3 in a race when only 6 (sometimes just 5) runners is betting madness. Your ROI will be very very small at best. Trying to cover all eventualities is NOT trying to win .. just trying not to lose.
Good luck, but I would suggest backing 2nd and 3rd favs .. or watch for any very late moves.

Not today, but finished 4th at 10/1 .. so place money gained (2/1 for place).