How long should I wait to see an accurate Performance Report in Performance Max?
According to Google, whenever you make any changes to automated bidding, strategies, and budget, you have to wait for at least 14 days (plus your conversion lag) to view accurate and complete performance reporting.
Conversion lag is simply “the delay when people click an ad and when they perform a specific conversion action (for example with, install, purchase, add-to-cart, etc.)”
What happens is the system will optimize towards what we tell it to do, so you must wait to make any changes for 14 days when Google can accurately assess performance.
Making any changes prior to that learning period will reset the account back into the learning period. This means, you’ll have to wait for another 2-3 weeks.