It can be useful to redo the GMAT Prep tests, IF you are honest about the effect any repeat questions are having on your performance. Still, especially if your skills are increasing, you will likely see few repeat questions.
Having said that, I can tell you that I have heard about high practice test scores which were not matched by scores achieved on the actual GMAT. THEN I find out that actually the high practices test scores were achieved via multiple retakes of the GMAT Prep tests, and that's much of why the practice tests scores were so high.
So I suggest not doing that.
By the way, if you have not used the Official Guide thoroughly, you may want to try the tests in PowerPrep, the software that preceded GMAT Prep. While sentence correction has evolved since that software was produced, for the most part the tests it generates rather accurately create a GMAT experience.
The thing is there is crossover between PowerPrep and the OG. So if you have done every question in the OG, you will run into repeats in PowerPrep.
You can download PowerPrep from here.
https://www.beatthegmat.com/mba/resources