Question regarding WPA2 rekey interval

I was setting up my wireless network and couldn't find WPA2 rekey interval row. Instead, I found somthing called Group Key Rotation Interval. Are they basically the same thing? By the way, is it ok to set it to 1800?

 

I think they are the same, but someone will correct me if I'm wrong.
I believe 1800 will be the rotation of the key in seconds (so, 30 minutes). So every 30 minutes, your key will rotate to a new one. If someone were to try and crack your key, they would have no more than 30 minutes to get it done.