What do you do about the edges? Do you just mop them up, or do you scrub them? No matter what, a buffer can only get so close to the edges and there will be at a minimum a few inches that have not been touched by a scrubber/buffer. Also, I assume that the floor is being burnished on a fairly regular basis. If so, the wax gets harder and harder with every burnishing, and wax that is hard like that, and is on edges that doesn't get much foot traffic does not like to come off very easily. You are most likely going to have to reagitate the stripper after you lay it so it will get through all that hard wax. Also, 4-5 coats is not enough for a grocery store. Try 10, five the first night, five on a second night for proper cure. Just because someone says you can cover x amount of sq/ft per hour, doesn't account for all the things that take up time, i.e. empty buckets, scrubbing edges, waiting for stripper to work, etc. With 3-4 people, I guarantee that you could only strip, AT BEST, 4,000 ft per hour. I have been doing this for 20 years, I have all the best equipment, great help, the time saving chemicals, and it still takes 3 of us 8 hours to strip and wax a 12,000 sq/ft store. No two strip jobs are the same. You might be able to fly through one with no problems, the next one you might have to restrip some aisles or scrape edges with a razor blade, or you might have ventalation issues where either your stripper is drying to fast or your wax won't dry. There is what you can read about, and then there is real world. Kinda like Estimated Miles Per Gallon on vehicles. The EPA may say a car gets 30 mpg, when in the real world, with real driving conditions, it gets 22 mpg. Just be careful about taking on big jobs when you are going from 1000 sq/ft to 20,000+ sq/ft, you should really consider working your way up to those bigger jobs, or hire a floor tech that can teach you the ins and outs of stripping a large job.