When you say the statistics for the interface are "wrong", do you mean they seem low or only about 50% of what you expect? This is because when you query the IP address of the SMO Master, you only get the counters for that one SGM and not for all SGMs in that entire security group. This is a current limitation of the SMO architecture; I believe the ability to get statistics from the entire security group is on the roadmap for the next major release.
Attend my online "Be your Own TAC: Part Deux" CheckMates event
March 27th with sessions for both the EMEA and Americas time zones