Sounds like there is no consensus on if this is normal. It seems like this just isn't the right shop for me both with date flexibility and pay. Ideally I would like if I could grab one every few months if there was a location near where I already planned to be for other shops.
As for the food being mediocre, the first shop I did the entire restaurant was filthy, the food had clearly been sitting out for a while and I was left with a pool of grease at the bottom of my salad. The second restaurant also had cleanliness issues and the food was adequate except for chips being over-salted to the point of not being edible. My reports were approved without issue even with all the negative remarks.
I wish I could only spend $7. Since I am not a big taco fan; with required items and city prices I can't get out of there for under $11 and that's without a drink. So my profit comes out to a lot less, especially if the food I am being reimbursed for is of such poor quality that I won't eat most of it.
I guess I just remember the food as tasting better in the past. I may also be spoiled by a great local burrito chain and I tried a new burrito place in my area last week and their shrimp & steak burrito may have been one of the best burritos I have ever had.