I think instead of 240 or 60 or 30 activities to become sr.member, member and jr.member
We should have 238,28,56 points to upgrade ranks.
Let me explain how it works with Jr.Member: It now requires 30 Activity points, which you can get in 29-42 days (depending on the day you start).
If 28 Activity would be enough, you could reach that amount in just 15 days. The extra 2 points make sure you need 2 weeks more.
Reducing the requirements for levels takes down the "value" of the level. So don't do it.