I have no workman's comp or liability insuerance, so I charge a little less than the going rate (but not too much less). I an limited to working weekends and nights because of my day job. But otherwise, I try to be very flexible with all my customers. I also explain everything that I can to them about the process, and why certain steps should be taken.
Take for example, I charge 1.75 sq foot for 10x10 room with 8 foot ceilings. By my calculations this would cost $175 with floor space sq foot, but with you method, it would cost $576.00 That is outrageous. Of course I didn't subtract the windows and doors, which is another thing that makes no sense. Cutting in around those windows takes more time, then just rolling a wall.
The price to paint an interior versus an exterior depends on a few factors. For painting an exterior, you will pay about $2,600. This is because you have to account for the siding, making sure the weather doesn't affect the job and dealing with weather conditions. On the other hand, the price to paint a home interior is around $1,700 -- less to worry about other than keeping the flooring and furniture paint-free. If you want to do both the interior and exterior, talk to the painters about any deals or their opinion on timeline and how it affects your budget.
"I had Sam and his team come in to repaint our kitchen cabinets that were originally a dark wood stain. He cleaned, sanded, primed, and put on 2 coats of sheer white on both the doors and frames of the cabinet and they came out great. The kitchen is much brighter and even up close it is hard to tell that the original cabinets were not white. They were prompt and very communicative over the phone. We may soon hire them back to paint the kitchen next."