The Last Stand ability says he moves the track two in his favor (unless it's 15). Does this mean that he cannot undo a Glorious Victory when the battle track is on 15 against him, or does this just clarify that you cannot go past 15 in a positive direction with the battle track?

I've been playing it where the he can't go past +15 but he can move a track from -15 to -13.

Thanks in advance for your answer!