Whipped cream

Ok, this is a really weird question, but this is driving me nuts.

Is there some difference between the whipping cream I got in the US and the whipping cream available here?

I mean this is not difficult...pour the cream in the bowl, run the mixer for 3-4 minutes, and you get whipped cream.

I run the mixer for 30 minutes and it is exactly the same consistency as when I poured it out of the carton.

Any idea what may be different?