^Exactly.
I think through the years as digital has progressed (and due to the earthquake) the amount of physical sales that is considered for 'gold' or 'platinum' (and sales in general) has gone down, hasn't it? I think the number is lower than before. I mean, 19k for first week of a single a few years ago would mean you were out of the top 10, let alone #6.
If you think about it, JAPONESQUE was still a #1 album despite being her lowest physical selling album since Affection! 'Feel My Mind' sold just more than JAPONESQUE at 154k and so did 'Grow Into One' with 200k, yet they were only #7 & #8 on the charts back then.
I think its because nowadays people use digital means to buy music much more than back then, especially through Itunes. However because Oricon's sales has always been the deciding factor on how well a single or album is doing, people still look to Oricon for that, even though digital is now just as big of a factor (if not maybe more) of sales nowadays. I'm not sure if Oricon includes digital sales, but I'd be interested to see how well kuu does with itunes sales, to be honest.
And despite Japan, South Korean sales are even lower physically, 4minute being a perfect example. With their newest album, 'Name is 4Minute', their album was at #2 with less than 15k of physical sales, YET their digital single of 'What's your name?' which was the title track for the album, sold 1.6 million! Which is an insane comparison. Even that is much lower than their first single 'Hot Issue' at 4 million, but despite selling more was only #3 at the time, and 'Whats your name?' selling less than half of that is at #1 now. It's no wonder Korean artists tend to sell more digital singles these days, cause they do 10x better. Not long after that, 4minute released another digital single 'Is It Poppin?' which made 1.5 million. When I first saw it, I thought "Another single so soon? Why didn't they just put it on the album?". Now I know why. xD
That's my theory, anyway. xD