Just a heads-up, Spirit Incentives is at it again with a new sleazy trick similar to what they do with the base-fare inflation on the companion ticket. Now, for the 15% discount, they're falsely inflating the taxes. From a few dummy searches, it looks like they're claiming the federal excise tax is 12% instead of 7.5%. I imagine calling in would probably get you the correct fares.

(Is this illegal in any way, in that it's essentially fraudulently collecting taxes? Or just really sleazy, as seems to be the norm for this company?)