It does indeed depend on the time of day. The MAN web site shows estimated waiting times at security. I can't vouch for the accuracy of this or whether it's bang up to-date but the difference in an hour is quite marked.
At about 5.30pm today, it showed T1 as 5-15 minutes; T2 as 15-30 minutes and T3 as 5-15 minutes.
Just recently at 6.30pm, T1 was up slightly to 15-30 minutes; T2 had extended to 30-60 minutes and T3 still 5-15 minutes. Yet as I write, T2 is back at 15-30 minutes.
Can anyone confirm whether the times quoted on the web site - not just today - are reasonably accurate?