hey brian,
just divide the bid that you received by the sq. ft. (floor space) of your home and you will have their equation.
Before you can bid a job and make money you need to know how much labor ( time ) and material it will take for each task. Overhead cost must also be taken into consideration.
Remember that a bid contract is a firm price agreed upon by both parties, so if the job is more involved or goes much longer than you expected, well ..you lose!
You cant lose with a time & material + profit contract. Time=labor/Material=material+?%handling /Profit=?% of each draw. Handling can be form 10%- 30%.Profit can be from 20% - 50% or more.
Check around to see what the painting market is paying in your area. The local paint store is a good place to start
Good Luck
Lynjowoman propainter