Very indicative of real test scores, but need slight improvement

I have given all 9 verbal tests in GMAT Club and 3 Quant tests, and can say the scores and difficultly level has been fairly indicative of my actual capability. Though I would caution to supplement this with other platforms e.g., MGMAT, Veritas which are slightly better
As other test series, GMAT club also pools these tests from a common pool of questions. At start, the quality was extremely good for 3-4 tests where I consistently scored V34-36, this was also my score on other platforms e.g., MGMAT, Kaplan. But then suddenly scores dropped to 25s, which demotivated me big time. I was consistently given 700+ questions (almost 60-70% of test) - I liked the practice but then the scores didnt mean much in my mind. Subsequent tests felt quite easy where I even went to V43, and of course was pleasantly surprised with this. But again I knew this wasnt my level cause I wasn't scoring it on other platforms. I assume something is wrong with their algorithm as my friend faced similar issue. But overall the quality of questions are good, and explanations satisfactory.
I scored Q50 consistently in my Quant - I was scoring similar on GMAT prep and MGMAT platform, so I think this is fine and nothing to highlight