I think my argument still holds. You may want to consider volume changes on a mesocycle level rather than the microcycle level for the reasons that Mike mentioned as well as allowing adaptation to occur. When dealing with high intensity components, it's always important to allow posture to be your guide during a session. If it begins to break down, maybe cut the rep in half and add a rep if you really feel that you have to get that volume in (which I would caution against).
Always be open to a "plan b". Personally, I might want to keep the Spec. End. volume constant throughout the meso. Might be tough to increase this volume at the end of a 3 wk block that contained a fair amount of high intensity work.
I think you are definetly thinking the right way, and that your plan is well thought out (shoot, when I was your age, I had no clue…), so I don't want you to think I'm just poking holes for the sake of it. Just want to give you something to chew on.