In Standard American is 1-P-2-P-
2 a reverse showing extra values?
What about 2 over 1 ?
The all too common “partnership agreement” is your answer here. Most of my partners play that 2 by partner after responder has made a 2 over 1 response (whether playing 2 over 1 or standard American) is simply shape showing and does not show extras so 2NT by responder would NOT be forcing in Standard American. Of course, in 2 over 1, you are in a game force, but only a couple of my partners play that 2 guarantees extras (at least a King extra). And a few partners play Flannery to show the opening hand with 5 (or more) hearts and 4 spades. When playing Flannery as 11-15, the above sequence would definitely show extras–16 or more HCP.