Understanding MAU and EAU difference

Hello!

Trying to better understand the MAU and EAU (external active users) difference
We have an essentials plan for 7.500 MAU quota all the time
When I check the plan description it says 7.500 MAU, but 100.000 External Active Users
I’m confused about the difference

so far there was a point according to the monthly reports when we had around 30.000 EAU
I assume if we exceeded the MAU quota that much we would have been charged way more, still that month payment was regular as per plan.

Could you please help me understand how these entities refer to each other and if there’s any way to extend the quota beyond 100.000 EAU if that’s hard limit or know more about pricing per user after the threshold is exceeded.

Thank you in advance!