Becky told me the same exact thing.
I know how you feel though. Despite the fact that Becky SPECIFICALLY warned me ahead of time about the E2 drop during that crossover to placenta, I literally worked myself into a frenzy that culminated in me bawling my eyes out in a Whole Foods parking lot convinced that I was miscarrying. The u/s the following day proved my fears wrong.
After this point that they see placenta taking over they stop checking beta and E2 altogether and just monitor P4. And once they're confident on P4 they stop checking that too.
On the one hand you're so thankful for all the dotting of "Is" and crossing of "Ts" but it comes with the price of near nervous breakdowns!