I did not say Mark was gonna reach 10% in two weeks, I said its prob only gonna take him two more weeks to reach 10% without any drugs in comparison to if he was on any.
And no, I did not say he was gonna reduce volume. I said he could split the same volume in that "shoulder day" into more sessions. Lots of studys (ex that norwegian one we talked about recently) shows that naturals do better with higher frequency than lower for the same volume in total.
Those two recommendations come directly from personal experience. I cut down to around 8% while not losing strength with no drugs last year and all my lifts increase faster since I've made the switch to higher frequency, going from a split to full body.
Anyway, all of the stuff I say is based on other peoples recommendations and science. I know I don't have enough experience to construct programs or give advice solely based on what I've done.