I don't think you are disagreeing with me at all. You pretty much sum my point up with this:

Instrumental reductionism, on the other hand, is only one tool for actually getting things done and, in practice, many situations involving large, complex systems are better tackled by simpler models that selectively ignore some or all of the "microfoundations" in favor of observing high-level patterns. It is nice, but not required, to be able to prove the accuracy of the high-level rules in terms of low-level laws.

This sums it up even better:

TL;DR version: Don't care about microfoundations. Care about tractability and accuracy. Just because a system can be reduced does not mean a reductionist analysis is useful.

The only major thing I can think of that you might disagree with is that microfoundations tend to increase accuracy.

FWIW I wasn't talking about epistemic reductionism at all.