new constrution with 2 x 10 joists.

Due largely to the crown of the dimensional lumber the floor rises and falls.  probably nothing more than an 1/8 of an inch, maybe 3 / 16 ths.  A six foot level may rock over a crown in the subfloor here or there.  Is this a problem with the installation of real hardwood floors or engineered prodcuts?  Should a leveling agent be used here or there?

I can of course as teh installers, however, I know from experience that many contractors wtih charge right in and do a job teh easy way and leave you hanging on the mess six months later.  So I would like to know upfront what a good install looks like.

Thanks everyone.