I've started solving OG questions after completing Manhattan rc, Manhattan Sc and powerscore cr bible. i've taken notes and made flashcards. i'm done with sc and cr from the og12 and my accuracy hovered around the 75% mark. I do time my og questions. almost all mistakes i make are stupid and i get 90% of the incorrect questions the second time i solve them. i feel that i'm wasting the OG questions by getting such a low accuracy in them. should i go back to revising concepts and practicing more problems? also, are the OG verbal review(2nd edition) questions as good as the official guide questions? or are they easier compared to them?