I agree.
On mildly reworked factory SBM heads, if you don’t do a fair amount of SSR layback, it’s not at all uncommon for me to see the flow continue to drop after the separation starts.
In other words, the flow gets worse and worse as the lift increases.
This is obviously not a problem with the area at the pinch getting worse as the valve is opened further, but rather the area of the bowl/throat getting progressively shut down more as the valve is opened.
In this scenario, if opening the pinch “more” exacerbates the situation, then imo, it’s not helping with power output.
It would make for an interesting dyno test though.
Bigger pinch with more separation and less high lift flow vs a smaller pinch with less separation and more high lift flow.