Pre-pay client accounting nightmare

With clients who have a prepaid account, when you go into their account, why doesn’t their Finances page show the balance of their account properly, as your Bank statement would?

e.g. A patient pre-pays £500, has 2 treatments of £40. Yes, the total shows £420 but on each line it should show £460 and £420 respectively, rather than -£40 each time. Whilst it’s easy for a couple of transactions, when you have to go back through several months or a client wants a print out of their account, it’s a true nightmare.

I did request this was looked at some months ago but nothing happened… Can you give me any news guys please?????
Thank you