So I understand that level 3 and above stands are the ones you require to charge grade 3 wheels, however what I don't understand is the purpose of the stand higher level than the level 3 ones. I can't find information explaining the difference between say a level 3 stand and a level 4 stand. The description on both is the same: "Holds three grade 1, two grade 2, and one grade 3 wheel."

Since no matter the level I can only charge 1 grade 3 wheel at a time anyway, is there any advantage at all to the higher level ones, such as faster charge times?