getting hired to do restaurant inspections for a big franchise and check on their franchised stores, how much?

I am going to be doing between 20 to 35 inspections per month, do routine monthly inspections on each of their restaurants that are franchised. like food, cleanliness, operations, etc. How much do you think I should be asking for each restaurant inspection?
I was thinking $60 or $70 per store. It takes around 2 hours or maybe even longer. I appreciate your help, again this is for a big 5000 restaurant Sub franchise.
Thanks

Will be more like 25-35/store