Make pre-discount field unchangeable when batch tuition posting

Customer has been editing pre-discount field when batch posting tuition and expecting it to alter the amount owed for that cycle. It was determined that the field was just intended to show any pending discounts, and was not meant to add or alter a discount for that family. Customer asked why they are able to change the amount in pre-discount field and advised would need a feature request to change.

Customer notes;

"When manually changing the tuition amount on a batch tuition posting, if I try to change the pre-discount amount, the system doesn't listen and just starts with that number. For example, if I were to post the below fee, but let's say I wanted to discount Thursday/Friday. I can change the "Owing" amount to $130.50, so it ends up being fine for total amount owed. The problem is when I try to change the pre-discount. It should start at $174 (which is 3/5 of $290 since we are only charging for 3 of the 5 days). The problem is if I change the pre-disount number, it does nothing, so on the ledger it should say something like $130.50 (with $43.50 discounted), but what it actually says is $130.50 (with $159.50 discounted). So, the end result is fine, but they are not getting a $159.50 discount. It is doing that math from the original number, not the modified number that we need it to be. Whenever we have prorated amounts, (3 times per year) I need to take about an hour to fix all of those."