4G no.of users increased after capacity upgrade!

Hello all
we have noticed a mysterious behavior when we upgraded a high loaded area with TDD , average no. of connected users has been increased although we had no new covered area and didn’t change mobility settings, noting that also no users has been shifted from 3G.

i’m thinking about 2 possible scenarios but i have no technical evidence to prove it:

1-area was suffering from very high DL PRB utilization so somehow very high utilization prevent users to connect without triggering any access failures in KPIs.

2-some UEs support TDD Bands only and does not support FDD (Bands 3,1,8) which i think it’s an out point.

would be thankful if experts here could help and please if possible with a technical description or document.