@emre, imo, I don’t see why having a different Cash tally would make a difference. One of the main reasons I use the Re-open and Cancel Payments function is to change Payment Methods (i.e. when the Ticket is mistakenly Settled to Cash, but should have been Settled to Credit Card).
As well, the Tutorial shows that you can theoretically apply Discounts, Gifting, or Voids after Re-opening & Cancelling Payments at the Order-level, which should change the Sale Account Amounts (though I have not looked at it closely enough to know if this is true.) Just be sure you are not only Re-opening the Ticket, but also Cancelling Payments. I haven’t tried Ticket-level Discounts, but Order-level discounts should work.
@teantattle2014, without having a little more detail about your setup, it’s difficult to say why this wouldn’t work for you any longer - especially since it (may not) be working at all, which sounds like a different issue having nothing to do with Ticket Discount implementation. Even the version you are running can make a difference sometimes.