Hello @OBDTeam,
Welcome back to the Klaviyo Community!
A common mistake I see often when comparing reports is not having the same metric selected - I would suggest checking there first. If the metrics used are the same, then this may be caused by how the attribution is calculated.
Typically, I would suggest using our custom reports as the performance report uses send cohorts to calculate its data. I explained a bit about this in a similar post which I’ve included below:
Since custom reports do not use our send cohorts calculation while our performance report does, you may notice some mismatch in the data all due to how it’s been sliced. Our Product team is working towards aligning this in the near future to offer a cohesive view at all your data.
David