And your post is complete bullshit anyways aside from your basic understanding of ABEC.
ABEC 1: 0.0075mm (0.000295")
ABEC 3: 0.0050mm (0.000197")
ABEC 5: 0.0035mm (0.000138")
ABEC 7: 0.0025mm (0.000098")
ABEC 9: 0.0012mm (0.000047")
Those are the different ABEC tolerances. For our uses, ABEC is completely irrelevant. .0063mm is not going to make one bearing "loose" while a higher tolerance is "tighter", and I don't know any scooter that reaches >30,000rpms, which is the only place that ABEC makes a difference speed-wise. ABEC means nothing, which is why you don't see respectable bearing companies advertising their ratings.