the builder simply has to do what you tell him, after all you are paying him!!
If you are not going to use the attic space as habitable space at the moment then theres no point bringing the insulation up and around its profile, you are better off just insulating between the ceiling joists..... because then you would not have to heat an unused space.
then if you do actually convert the attic for habitable space in the future, you can insulate accordingly, plus you would have insulation in the 'floor' which would aid in both acoustics and space heat zoning.