Variability in Scores? one, understand, practice, another, seeing

AndyNZ

Is anyone else seeing massive swings in their practice exam scores? My score on Schweser mocks has ranged from 61.6% all the way up to 91.6%. The 2 CFAI Mock exams were no better, with one score of 55% & another of 86%. I understand that this means that I have weak areas to work on (FRA, Swaps, Ethics) but this range in scores is freaking me out.