When you move up to the 5370 and beyond, that is quite a step upwards in terms of finishing and there the double assembly also kicks in.
Is this correct ? I though the 5370 was based on the same movement as the 5270 (and 5170), but based on the below picture (not mine alas) the finishing does seem to be nicer (taking into account that this is a professional picture whilst mine is far from it):