Zoom admin access over whole org vs zoom admin access over specific group

We are using dashboard meetings api to list all meetings .
Context :-
1. Zoom admin access over whole org generated 10k meetings but zoom admin over specific group generated 64 meetings. Filtered out 10k meetings on the basis of users present in that user group, it boils down to 2k meetings.

Questions :-
1. There is difference of 2k meetings, so we observed that admin access over specific group is giving meetings from date of creation of user group. Is it limitation what zoom offers that it doesn't consider past meetings? 

2.  We compared meetings for same day there was difference of 60 meetings, is it another limitation that it will give those meetings which have all participants from that user group?

Can you give resolution to above questions?