Question about canceling StraighterLine account

I'm not a huge fan of automatic billing. I know I can cancel straighterline at any time, but I'd like to know, if I do so -- is it effective immediately, or does it not take effect until the time you've already paid for is expired?

I know with Aleks that if you cancel, your account remains until your renewal would have been due, and I'm just wondering if SL is the same. I can't find an answer to this on their site, so before I call and ask I figured I'd check with the experts here.