The ledge of 3675 seems to be smaller than that of 3298 (left) (smallest modeled in the library) but larger than that of 3037 (right) (not modeled).
Since this part is the only one I've seen where the under side of the ramp is not parallell to the top side of the ramp, is it okay to assume that it should be there, and update the part?
Also worth noting is the fact that the ldraw version of 30363 has the ledge come all the way to the edge of the underside tube:
but the real-life version does not:
and the top and bottom seem to already be parallel:
I am currently starting my first MOC, which is basically my first project. I will add additional levels, i just want to know if there are things to change before i get everything set