Theory 1, IMO
dmp802First, judge your lather on Quality, not Quantity. Does the lather in Pass #1 do an effective job of providing glide and lubrication? That's all that counts.
If you have to reload more soap or cream for Pass #2 and #3, its not a problem.
I exclusively face-lather, and I very rarely have to reload my brush. I get enough lather for 3 passes with plenty left over. If I'm using soap, I load the brush with about 30 seconds of swirling on the puck, this builds up a pre-lather that I finish when I put brush to face. If I'm using cream, I will squirt a snurdle on my hand and apply it both cheeks and my neck, then distribute it by hand working up a pre-lather in the process, then finish the job with the brush.