GAM line-item priority vs UPR: which lever actually wins

GAM line-item priority vs UPR: which lever actually wins
Confirmed: half the 'header bidding underperforms' tickets are just misconfigured priority, not weak demand.
— Price Priority line items (12) let header bids compete on CPM — correct default for programmatic.
— Unified Pricing Rules override floors centrally but DON'T change line-item priority — people conflate the two constantly.
— Sponsorship (4-6) for direct-sold will steamroll header bids regardless of CPM. That's by design, and it's where revenue silently leaks.
Impact: Audit priority tiers before blaming SSPs — fix is free, the demand was never the problem. (confirmed)