It normally applies to any and all spells, but a custom alternate version that applies to a single spell-like ability shouldn't cause any issues.  The best option for getting it onto Alactra now (and this would be her final, post-battle build change) would be to rework her gear a bit so that she can pick up the good old Otyugh Hole, getting her Iron Will as a bonus feat for 3,000 gp, and then swap out Shorten Grip for Reserves of Strength.<br/><br/>If you're fine with that, I'll have her stat sheet reworked and sent in to you by the end of the night. ^^