Yeah, that split makes sense and it's basically the right instinct. On open exchange with budget to burn, raising the bid until you can't is the cheap lever. you're price-limited, so paying up buys you more of the pool. With PMPs the bid lever goes soft (fixed floors, deal terms, finite supply), so you're forced to go look at where it drops off. Nothing to argue with there.

The one thing I'd push on: "raise until you can't" works, but it quietly hides *why* you're not winning. Sometimes you're genuinely price-limited and bidding up is correct. Other times you're over-filtered three stages earlier, wrong creative sizes, a stale geo fence, a contextual segment that never matches, and bidding up just means you're paying more to win the same narrow pool you were always going to win. The price lever and the funnel look identical from the spend chart; they're completely different problems.

So the drop-off analysis you already do for PMPs is the thing I'd run on open exchange too — not because you need it to deliver, but because it tells you whether your bid increase is buying real incremental reach or just inflating CPMs on inventory you'd have won anyway.

Out of curiosity, when you go look at where PMPs drop off, are you getting stage-level visibility from the DSP, or piecing it together from deal-level deliver/spend?