What's up with the taper for A races in HV tri plans?

I’m getting ready for St. George in 10 days, and have IM Thun on the calendar for Sep 5. Thun was just moved from July 11, so I tried switching St. George from a B race to an A race, since 1) I now have more time between races, 2) nothing is lazier than an athlete on taper, and 3) I was thinking that this would result in a more severe taper.

However, the taper was actually much less severe if I made St. George an A race. In fact, there were some damned hard workouts in the last few weeks. So I switched it back to a B race.

Same seems to be true for the Full – the week before the IM is one of the biggest TSS weeks in the plan.

What gives? I want to put my feet up on the couch and eat some muthaflippin’ bonbons!