If the feat is there then I'm not going to ignore it. Jiraya said the same thing about his sm, of course no one cared then.I don't think it should be a factor if Minato said it not being his forte is an understatement, so we should stop having this debate and move onto the actual battle.
The throwing of the kunai, the sand wall, the motion lines and the effects of the pigmentation appearing around Minatos eyes all indicate the speed of which he entered sm. All are relevant.