Data Request Charges

Does anyone here use two accounts both using the api?
I'm considering buying a second licence for an api product. I want to know if I can use 20 requests a second per account? Do they count all requests from all accounts and if there over 20 a second then apply charges? Or can I have both accounts using 20 requests a second each?

I did email betfair but only got the usual copy and paste reply.
Thanks