Reserves and early prices

[slapdash]

Just idle curiosity ... In some Irish handicaps, there are reserves who get to run if other horses are withdrawn. Does anybody know for sure how early prices get dealt with in that event? Paddy Power's rules say that the price of any reserve that runs is offset against any rule 4 deduction. I presume this means something like: if a 4/1 horse (20p rule 4) is a non-runner and a 12/1 reserve (5p rule 4) takes its place, then if you've taken an early price on another horse, there is a 15p (20p - 5p) deduction? What if it were the other way round? A 12/1 horse is withdrawn and a 4/1 horse takes its place? Do the odds you get on another horse increase? I'm guessing not. ;)