Blog hinted at super low numbers for this week, most likely due to stock issues.
I passed again tonight by Labi shibuya and they had stock, both slim and pro, same as this weekend. It's anecdotal of course, but it's a big store and one of the first I would expect to be out of stock.
Historically we've seen this happen before where a model/SKU switch did not line up well with existing production phase out - eg. PS2 -> Slim switch led with several weak months of Fat model being phased out, than followed by weak months of Slim production not ramping out sufficiently quickly.