The main reason why Warmoth can't do a level and dress along with a truss rod adjustment is because there are too many variables beyond their control. Until that neck is put under tension by the strings and settles in, there is no way to know in advance how it will need to be adjusted. And without a proper truss rod adjustment, you definitely would not want to look at doing any work on the frets. Other variables to consider are climate conditions in your area (temp, humidity) and what gauge strings you decide to go with. Heavier strings obviously put more tension on the neck. People like Gibson, Fender, Shur, etc. can and do perform that final stage of neck/fret work in-house, but they are also working with a completed instrument that is strung up and under tension. Even then, stores and buyers have to take them to local luthiers/warranty centers for final set up under the manufacturer's warranty if something settled and change during shipping or while getting worked over in the store by a 13 yr old Slayer wanna be. We have Tim's Guitar Workshop here local to me. He is a warranty center for most guitar manufacturers and does this all the time for Gibson, Fender, Ovation, Martin, etc.