We are getting very close to signing with PD now - even have a block of land ready to put an offer in

I have been interested to read since joining Homeone how people continually say 'Don't get flooring done by the builder - too expensive' etc
I am just wondering are they really that much more expensive? Is the difference between getting it done by the builder and getting it done privately huge?
I wanted to get timber floors in majority of downstairs and carpet in majority of upstairs...
I have budgeted $10,000 for carpet and $15,000 for timber floors....
I'm just thinking that it seems simple to get it done by the builder - done prior to handover, include it in the loan, not having to source flooring elsewhere, ring around for quotes etc. I am willing to pay a little extra just for the convenience.
BUT if they are going to charge something crazy obviously I would do it privately.
Thanks for any help - if you could give examples (especially PD people) that would be awesome!
Bel
