Do anyone know if the VGChartz tracking for PSP is UMD sales onyl or it's UMD + PSN sales? Since PSN version of the game is rising in popularity because they are cheaper than the real counter part. For example, Valkyria Chronicles 2 on the PSP was 5,500 Yen retail, and only 4,500 on PSN. Anyone know the answer to this question?

UMD only. Looks like vgchartz isn't tracking digital sales (steam, PSN etc).

Also, PSN and Retail are separated:
http://www.vgchartz.com/games/game.php?id=40205&region=All
http://www.vgchartz.com/games/game.php?id=35592&region=All

:/ doesn't seem consistent... oh well... anyone think they have a good estimation of the digital sale of PSP games on the PSN based on UMD sales?

The problem is that there's just no way of getting Sony to reveal the numbers they get from PSN. You can't just go inventing numbers like that, unless you can compare them to something

Well, we know GT PSP has shipped about 1.8m, and sold around 1m on VGC when that sales data was. Given how high their GT 5 Prologue numbers are, it is assumed that Polyphony's sales are including PSN data

So, that probably means it has sold about 500k on PSN, given there are some sitting on shelves

This is where I am getting the numbers from:
http://www.polyphony.co.jp/english/list.html

GT isn't really a good baseline given it was a free download for European PSP GO buyers, which would HUGELY inflate it's numbers.  That alone could account for 500k+ pretty easily.

The only actual mention of PSN vs UMD sales I'm aware of yet is from Atlus concerning Persona PSP in Japan.  It sold 150k on UMD and just 10k on PSN.

It's hard to imagine PSN sales being anything major considering there are companies dropping support for it entirely because of piracy.