Yes they will need to blend it otherwise it will be off color. slightly off on certain angles. yes... they have to take off your clear bra and will cost more cause taking that out is a PITA... if your not going to blend it... specially on a mineral white thats going to be tough to do without blending it through hoods and fender.
not sure if your in Los Angeles Area but i have been going to the same body shop for years and have done an excellent job.
if you are in LA area... pm me