This is because some shops' sales don't count towards ORICON even though they still sell albums, singles, etc?
Yep, ORICON is mediocre and useless
EDIT: And not to even mention all the sales that are missing from the concert venues, since ORICON only counts a percentage of them? I still think this is not fair for anybody, if they think the companies are trying to boost their artists' sales (which is fair enough I think), couldn't they have people there making sure they aren't cheating and getting dodgy numbers? The percentage thing is just ****ing stupid, I hate it.