Max Signature Stone when hero already has some Signature Ability

HongKongPh00ey

If I use a Max Signature Stone on a hero that already has some Signature Ability what happens to the excess? For example, if I use my 3* Max Signature Stone on my Daredevil (Classic) and he already has Radar Sense 20, the Stone will max his Ability to 99 but do I get 20 Signature Stones to make up for what he already has? Or do I just lose that 20?

DoctorJ

You just lose the difference