Slush's pool n00b question

I joined Slush's pool 9 days ago and to start mining and joined the forums today because of an apparent issue with my past block. I'm just trying to figure out if I'm doing the math right here, cuz something doesn't seem to add up, albeit a question of about $1's worth of Bitcoinage. If I take the total shares and divide it into my shares and then multiply that by the block value (BTC) I should get my BTC reward, correct?

For example, my last round I had 166670 shares of the total 3490051507, with the total block value of 25.03846456. My BTC reward was .00000928 for that round. I'm pretty sure it should be more like .0011957304 (not counting 2% fee).

166670 / 3490051507 * 25.03846456 = .0011957304

This reward is more in line with my previous block rewards....or do I just have no idea what I'm doing here? lol

I've only started looking into Bitcoins about a month ago, so I'm still pretty super n00b with this.