Questions about paging group.

1.what is the impact of having different paging groups in one single LAC?

example:
In LAC = 100

I have 33 cells such that 18 cells having AG_Blocks = 3 and MFRS = 4,
while the next 12 cells
having AG_Blocks = 2 and MFRS = 4
and 3 cells having AG_Blocks = 2 and MFRS = 5.

2.If we have the IE as “IE indicates specific location areas”, who will calculate the paging group for each IMSI(TMSI)in downlink, BSC or BTS?

Thank you very much.

BRs,