Say, for example, you have an account with two campaigns. If you set a cost per month goal of 500 EUR/month for each campaign, Adspert will spend approximately 1000 EUR per month - which will be evenly distributed among the two campaigns.
On the other hand, if you set a cost per month goal of 1000 EUR/month for the entire account, then you’ll still spend the same amount each month - with the difference that Adspert will spend more on the campaign that generates cheaper conversions (or significantly more revenue) and less on the other campaign.
This, in turn, leads to more conversions compared to single campaign goals for the same monthly ad spend and is why we always recommend setting goals at the account level whenever possible - to give Adspert the freedom to optimize accordingly for the best possible results.
The above procedure is similar for CPO, ROI, and CRR (or ACoS) goals too. If you set a CPO goal of 10 EUR for both campaigns, then each campaign will have an approximate CPO of 10 EUR. The CPO for each campaign may vary if you set a CPO goal of 10 EUR at the account level and Adspert will optimize in a way so as to achieve an overall account CPO of approximately 10 EUR.