CBSubs just sends iDevAffiliate the purchase price. The commission amount is handled by iDevAffiliate exclusively. I don't know if iDevAffiliate has the feature you're wanting. We send the plan id as data option 3 so if you're able to condition a commission based off its value then you'd have plan by plan commission amounts.
PostAffiliatePro gives quite a bit more control over commissions (e.g. campaigns, channels, or even custom plan by plan commission) if you're looking for something more powerful.