Why are plan limits based on total contacts instead of contacts actually being synced?
In order for us to determine whether we need to add or remove a contact to/from a custom audience, we must check every contact in all connected apps.
The same for leads. We have a backup system that double-checks all leads in case they fail the first time.
This happens rather frequently, unfortunately, because of very short timeout thresholds from Infusionsoft. It may also happen when Facebook webhooks fail, high network traffic, we are having an issue ourselves, etc.
That sweeper system that double checks, like the custom audiences, has to check against all contacts in the app. So as contacts go up, our resource requirements don’t just go up, they go up exponentially.