Rabbi Meir ben Yitzchok of Eisenstadt, Ponim Meiros - Meir Eisenstadt = Panim Me'irot = Maharam ASch

technically you can apply it to the Ponim Meirot because its the Acronyms of his name Rabbi Meir of Eisenstadt (Ash is in Brief for Eisenstadt), but the term MaHaRaM ASch was used for a Much Later Rabbi the Rabbi Meir Ash of Ungwar (https://en.wikipedia.org/wiki/Meir_Eisenstaedter)

and the first one was in fact called only by the term the Ponim Meirot!