Sometimes scoring 5/5 without BR

Sometimes scoring 3/5 with BR or

5/5 with BR

My track record for MSS are all over the place and I can't find the underlying theme or thread for why I can't be consistent in my scores.

I found that with MP questions I was able to figure it out and find a strategy that worked but are there any tips on this?

I think I'm just not understanding MSS..

(even though I've learned that the stimulus holds the premise and the answer choice holds the conclusion)

I'm concerned - any thoughts anyone ? :$