How to process google CSV payout reports?

I have an headache because of idiotic google payout report format. I am just no able to normally work with them. Doesn’t matter if I open them in MS Excel, or convert to google spreadsheet, I just can’t make it without most common error - number are shown as dates often. Whatever I do, I just can’t. I have a tons of work checking whole list and repairing problems. I am crazy about that!!

How do you deal with it?

In Open Office selecting US English as language solves it for me.