That is incorrect for instance Ernst Barkmann was using a Panther.
"Barkmann Corner"
Yeah I actually googled for Panther Ace after I made that comment and found out about Barkmann but the other half of my statement still stands, most Panzer Aces were in Tigers.
Kurt Knispel, Martin Schroif (Relic even gave almost the same name to the driver of the Tiger Ace), Otto Carius, Michael Wittmann, Hans Bolter and others are just some examples of Tiger Aces.