I would say it's not necessary to have a multiplier on hardsigned autographs. The reason we have a multiplier for jersey cards is that you are comparing the exact same card with itself... just with a different element (swatch).
Comparing one hardsigned Gretzky autograph to a sticker Gretzky autograph from another set should not yield a multiplier on the hardsigned one. That's why each set has it's own price guide listing. It's not like it says Gretzky 03/04 SOTT (2x Gretzky 04/05 All World Autograph).
I think the "only" case that could be made is the Ice Glacial Graphs vs Ice Glacial Graphs Sticker Variation. Then you are comparing the same exact card, but one is hardsigned and the other is not.
So "no" to a multiplier.
