no i think the "3rd grade level jutsu" applies to jutsu abilities as a whole...
and 6 grades above the 2nd "a rank blah blah level" means that whatever level the 2nd A rank level is, he's 6 levels above....but that applies to him, not the rasengan, which jiraiya did on purpose to show naruto that someone at a level as high as he was still needed 3 years to master the technique