General GMAT Questions and Strategies | Seeking advice around CATs

Hi there, any advice is appreciated on my two questions:
1. I am planning to take 4 more CATs until my exam (July 14). Would my time be better served reviewing by other means?
2. MGMAT Exams 5 & 6 - or - GMATPrep Exams 5 & 6 (EP2)? I ask because there is a large discrepancy between my performance on GMATPrep and MGMAT CATs

Context:
- Sitting for GMAT on July 14
- Did 6 CATs already (reviewed MGMAT material between exams) - details below
- Leaning towards taking GMATPrep 3 & 4 and MGMAT
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