Wanna know what will probably improve your USMLE score at the end of the day?
Do it in tutored mode (for some time) and don't even bother "ending the block". I started out lower than you and was always freaking out about my percentage but it really doesn't matter. Then do random when you start getting more comfortable with the format. Half of UW isnt about the knowledge its about sharpening your test taking skills.
Go at it for a few weeks reading all the explanations and your scores will naturally go up. When they say its a learning tool they mean even getting the answer right isn't the point; the point is knowing why the other 5-6 answers are wrong
Do that and then do your incorrects/or 2X while using the other passive resources and you will be okay. You dont want to "improve" your UW score, forget what all the gunners on here say about their "first pass 92%" BS. Just use it as the excellent tool (not assessment) that it is. Use weekly NBMEs to assess.