sorry everyone if this sounds stupid...

but I'm having trouble with my methadone balance...I don't know how it happens but I seem to run into 'negative' quantity of methadone balance... even though I'm sure I've entered everything correctly (having corrected a few 'normal' and 'SF' mix ups, etc)
I know it's my fault I haven't been calculated the balance everytime I enter the register (due to lack of time, calculator, etc)... so I couldn't recall when I've went wrong!


I've kept most of the methadone invoices copy from Sep 07 (some I have lost...

), I've re-checked them again but I seem to have entered all that has to be entered! Can anyone give me any advice?

Thanks!