PSVita launch week sales:321k

[theprof00]

Acevil said:

VGKing said:
That's double the PSP debut sales and almost 4x the PS3.
Impressive.

Well to be fair, PSP only had 1 day sales vs 2 day sales that that the 3DS and PSvita had. 

Just for my own understanding, where does it say that psp had only one, or that the reported number was for only one day?

It seems odd that famitsu would say that the vita opening beat the psp opening by double, if in fact it was simlpy because it was 2 days vs 1.