Subject: Grandpa goal

Because it's random of course!

It doesnt drop every week, it has a chance of dropping, and can drop like 0,5 or 0,7 of a full level (or whatever)... the older, the bigger chance of a drop... but many weeks, there is no decline at all... and by random, means there is example 10% chance of a drop and then you can be lucky or unlucky... which is also why one skill can drop several times before another skill drops at all...
(edited)