I do.
There are as many ways to load as people that load.
Right or wrong... I figure out how long I can load in my magazine. If I hit the lands, back off by a couple thou and do an OCW. If there mag is the shortest part of the equation, then I'll load to mag length and OCW. Usually I'll find something just fine.
The reason is, at least in my feeble mind, changes in length will slightly change volume and pressure... so I will have a different velocity if I do seating after.