I have a piece of ductwork that has (2) sq-rd's on it. i drew the pieces as they would be fabricated. i used the sheet metal loft feature to make all the sq-rd's, but the flat layout is not coming out right. the flat layout shows the straight edges will have an arc to them (which shouldn't happen). also, the round end is not working out. i should mention that i already cut these parts and am in the process of assembly. when forming a square-round in a press brake there will be a triangular shaped area that is flat. my model shows that the flat will have a curve to it. is there a way to make these parts so they flat layout correctly?

the computer model, of course, shows that everything should work great, but that's definitely not true in the real world.

i attached the file, so hopefully someone can help me....