Using Eulerian's One for Each model, the gaps between Meta's performance as displayed by Meta on the one hand, and Meta's performance as displayed by Eulerian on the other hand could be reduced but can never be identical.
Eulerian counts a Meta click when the user arrives on the Client site.
The click to landing page rate of Meta campaigns can vary between 70-90%.
The two platforms therefore do not measure campaign performance on the same signals, making comparison impossible.