Inspired by Uri Peleg's excellent first video, I've been trying to understand more of PIO's hand selection choices, and I've found one I can't explain.

The set up is BvB when we open, check, and face a bet. I've given BB two sizing options - 30% and 75%. The board is T94s.

What I notice is that when he bets large, we pretty much always check/raise J4s, and the other 4x combos are mostly a check.

But when he bets small, A4s becomes the most check/raised 4x, and J4s is a check/call much more often.

Could the reason be something to do with not wanting to raise J4s vs a smaller sizing because the SPR will be more difficult?

Here are the relevant nodes: