I just self graded my first AM practice test. For questions that have multiple questions, I’m just dividing the number of minutes by sub questions. e.g. If question 3 is worth 9 minutes, and there is 3a, 3b, and 3c, then I mark of 3 points for each one of those I’m getting wrong. No partial credit on the “sub question”…but partial credit on the overall question. (so if I get 3a wrong, but 3b, and 3c right then I scored 6/9.)
Are you doing Schweser or CFA mocks? Schweser gives guidance on how to grade your own exams. They also recommend applying a 10-15% haircut to the score you give yourself on the AM section.
For calculation questions - if I can logically explain all of my steps and arrive at the right answer, will I get full credit if I don’t use the CFAI formulas/methodology? My approach can be entirely different, but logical (and arrives at the same answer!).