If you are matching existing doors in the home, it is recommended to follow what has already been established in heights to keep the same uniformity throughout your home.

A 6'-8"-7'0" door is typical within a home - but the frame around it can vary from 2"-4".

I would stick with what your builder is saying to match the existing. The craftsmanship will just have to be especially thorough in that 6" of space between the frame and the ceiling.

Thank you! We have raised the ceilings in the main section of the house -- bedrooms remain at 8 feet. So they want us to raise the headers of every doorway, including the old existing, so that every doorway regardless of ceiling height is the same. We are worried that such huge doors will look ridiculous in a room with 8 foot ceilings, and that 2 inch moldings around them will look too skimpy. What do you think?

Hmmmm, I can see both sides. It would be nice to raise the headers so that the doors look uniform in height, but I can see your point about the huge doors. If I was you, I would look at it from a financial and aesthetic standpoint.

If you can afford it, I would raise the headers. OR if you feel like the aesthetics of the room will be compromised then leave them. Without me seeing the space its a hard call. Hope this helped.

Taller doors will actually make your ceilings appear taller as the vertical lines will accentuate the height.