I'd like an opinion on the following scenario. Say you're doing cookie cutter houses for a builder. Labor cost is $1400, material is $1000 - total cost is $2400. Mark up cost 125% for sell price of $3000, for GP of $600 (20%)per house. The buyer of one house works at an electrical supply house and wants to supply the material, thinking to save some money. Using the same method as above, the sell price would be $1750 ($1400 cost X 125% MU). This leaves a 20% GP of $350. Same 20% GP, but I just lost $250! What I did was take the $1000 material cost from the standard $3000 sell price for the new sell price of $2000. Still made my $600, but buyer unhappy. Was I wrong figuring this way?