Actually Super Vegeta is Vegeta in Ascended Sayian mode. He just calls it "Super Vegeta".
Of coarse, the word Super in front of a name without the "Sayain" part means different things apperantly. Vegito calls himself Super Vegito when just transforming into SSJ1. And Gotenks calls himself Super Gotenks at SSJ2. So really, they're just saying that in place of what level they're on. Though the games call Vegeta in his Ascended Sayain form Super Vegeta cause it's shorter than Ascended Sayain Vegeta, same for Trunks.