They're dirt cheap, the drain is rarely an issue unless you take 3+ ranks, and you typically get enough hits that you can activate them prior to combat. If they affect everything, they should be more expensive.
Actually, I forgot to add something & you mentioned it.
Given the Levels are the Drain but Magic is a huge chunk of the dice I think the Drain needs to be increased.
I don't think it should cost more in PP. But I do think Drain does not work properly.
I'm thinking either 2D/Level, so twice what you currently have.
Or
Drain = Magic/2 & levels mean nothing since your level has PP cost associated where the magic is kind of free with Attr-Boost.
If you were resisting Drain-3 (Magic-6) for every boost trigger I would have no issue with them affecting all parts of an Attr.
Possibly Magic/2 + Levels Drain but I'm thinking that might be too harsh. 5 Drain for a Full Magic-6 Wolf Adept to trigger seems way too much to me.