Hello :)
About the stacking of T1 - as some member do not have their vote at 0.03 value yet, we do allow them to stack up with their 100% too. As long as the T1 is achieved (by 0.03 upvote or 100%) it can be stacked to any higher Tier.
So your example...
By way of example, if I 100% upvote 7 posts/week at less than the threshold AND delegate 100 SP AND send 1 Steem per month. Is that a T2 or T3 scenario?
...would give you T3:
100% upvote (T1) + 100 SP (T1) + 1 Steem (T1) = T3
Looks like we have been lawyer :p
Theoretically your calculations are right here. If someone upvotes with less on more posts the total value in a week would match. But it would make a hell to admin for us if we start allowing exceptions like this. Thus we tried to unify it for everyone and make it simple by upvoting 7 posts a week.
Thanks for the detailed response! And I totally understand about the administrative issues. I was not sure what the back-end looked like for you guys when you are measuring people's upvotes. If calculating weekly upvote value is more complicated than tracking whether or not someone votes 7 times at 100% or $0.03, then I agree with sticking with the system you guys have. It is a good one.