Question about rakes as it relates to bonuses.

This isn't a complaint, I am just interested in the reasoning behind it.

I will use Absolute Poker as an example as that is the bonus I am currently working, but I have noticed this at numerous sites. At Absolute Poker, you are credited with one "point" at a ring game for participant in a raked hand of 25 cents or more. When you participate in a STT, however, you get one "point" for every dollar in entry fees you pay. It would seem logical that you should get more "points" for participating in a STT than a ring game (as you are contributing so much more) yet this seems to be the case at nearly every online poker site. Is there a particular reason why, or is this simply the way it is?

Thanks in advance.

Chris