You are likely sick of hearing from me by now but I like to learn first and do second.

We are finishing out homes basement. For starting to frame the basement walls it was suggested I tapcon my pt baseplate to the floor right up against the 1.5" of XPS I put on my walls and instead of using a top plate attached the 2 X 4s to the rafters above, ie simply tie the 2 X 4s into the base plate, level them up and attach to the rafters above...which are already spaced on 16" centers. Never heard or thought of this.

Is this up to code? What do you all think? Plusses / minus? My joists run in right direction for almost all my walls....sound so much easier than erecting a wall on the floor or toenailing etc.