We set budgets at the campaign level and the portfolio level, so which budget gets priority?
When the portfolio setting "Auto adjust campaign budget limits" ISN'T enabled, Media Optimizer will stop spending on campaigns when they hit their campaign budget limits, whether or not the full portfolio budget is spent.
When the portfolio setting "Auto adjust campaign budget limits" IS enabled, Media Optimizer will automatically adjust spending limits for the campaigns in the portfolio to maintain spending for the entire portfolio, based on expected daily spend. Additional settings determine the minimum and maximum budgets (multiple) for the included campaign.
Hope this helps!