This is like my passion topic. What you are struggling with, I struggle with myself, and..yeah, dark times, lol. Then, I had this epiphany (not joking) with the help of 7sage gurus, realized what I was doin in my active reading, was as a reader instead of part of the conversation where we engage with the psg almost as an dinner partner, where the guy sitting across from you is talking your ears off, but you are not merely comprehending the conversation(psg), but an active participant. This also makes the psg afterwards feel like a conversation that you don't have to memorize to relay it, and using this hack took me to a level on RC I didn't think was even possible.

I think that's a really common issue that's plagued a lot of us. Are you usually short on time by the time you get to 4th psg? If so, it might be helpful to start trimming a second here and there on the easier psgs & questions to allow yourself a little more breathing room. But if you do give 4th psg enough time and just don't find them enough, I would also look for any commonalities in those psgs to identify where might be struggling, and a with a little practice, the sky is the limit.

I was wondering about that too, but I have a suspicion it's related to timing. All the circles ones on mine were over the average time.

/A->/B, in the simplest terms for me, would be /A->B. If you want to negate the contrapositive of the original diagram, the contrapositive would be: B->A. and you can negate that as B->/A