One of the things I'm noticing about ARX treatments (I'm in the process with three of my vehicles right now) is that all sorts of things stop and start and stop and start again during the treatment. Leaks stop for awhile, then start again (although much smaller than before the treatment) then eventually stop altogether, check engine lights (CEL's) go on and off, the engines run smoother-rougher-smoother and so forth. Even operating temps change! So, it isn't surprising that oil usage varies during the treatment, too.
I KNOW that a lot is going on with ARX in the sump, and years of crud are being liquified and removed... this apparently affects a lot of things while the process is ongoing.
The payoff is that once all of the cleaning and rinse phases are done, everything should be a LOT better than it was before - at least as good as it can get from a total and complete internal engine cleaning.
Obviously, ARX can't fix excessive wear or other purely mechanical problems, but like the ARMY ad says, it helps your engine, trans and diff to "be the best they can be."