Sorry, I should have been clearer - all of those coupons were left over from the first transaction. When I looked at the register after the first transaction, I thought the numbers looked weird, so I took a screenshot without touching anything.
Oh I gotcha! No worries! haha. Yeah, so you can work down totals without zeroing out categories. :) Some coupons only effect categories and some effect totals (like Rebate Slip gives you 20% off the total but doesn't touch any categories). I double checked the coupons and they all seem to do what they should be, however I think that the mechanics are just honestly a bit over complicated and I need to simplify them. For example using a $5 off meat coupon with a meat category of 3 still gives you $5 off the total because the category wasn't 0, but if the meat category is 0 it doesn't give you anything. So for categories I probably need to make them more strict on "You can only reduce up to the amount the category is set to". haha