Im trying to understand how the affectation rate works.
It works fine thank you

Right now I leave it at 100%
IT is default, and works fine in many cases.
and doesn't seems to be logic.
all depends what you expect
To match the productivity with the affetaction rate I was wonder in what time frame is based.
It is based on a daily bases.
Once again RTFM : hit F1 on Activity page, move 2 pages up to get to page 3/5 of activity, whare assignment is explained.
I have activity type A that I can do 2 per week, and activity B I can do 4 per week.
2 what, 4 what.
Number of activities ?
If you have activity A, it means you'll work on this activity, not run several times activities of this kind...
Weekly basis affectation for type A is 50% and for type B is 25%
This means (to explain) thant you can work 0,5 days per day on A and 0,25 days per day on B (respectively 4 hours and 2 hours for 8 hours day).
Monthly basis (lets say 4 weeks) (8 activities) type A = 12.5% (1/8th) and (16 activities) type B = 6,25% (1/16th)
Or in yearly basis (52 weeks) type A = 0,96% (1/104th) and type B = 0,48% (1/208th)
You lost me there

I'm afraid you have a unit issue : projeqtor is Work driven PM tool, so you have to deal with "how many days (or hours) I'll work on this activity"
So in what time frame I'll need to measure productivity to be related with affectation rate?
In days (or hours dependeing of global parametering)