Anything interesting about WAC and WAM?

CFA Level II
#1

I found through a mock, that you can use your WAM to help you figure out the “n” in figuring out CPR through PSA E.g. the WAM was 356, so that meant that we were 4 months into the life of the bond. So you used that to find the CPR through PSA.

Anything else interesting that you can think of regarding WAM and WAC that is useful for the test?

#2

yeah I still dont know how to calculate interest Plus principal amount for a CMO

interest = WAC/12 * notional amount? what about Principal Payments?