VPN port speed reading in RAS?

Is anyone familiar with the port speed reading that appears in the event log after a user closes his/her VPN connection?

here is my situation:
I connect to my ISP at 28.8kbps.
I then initiate a VPN connection to my VPN server and it also connects at 28.8kbps.
After I disconnect and check the Event Log. It reads that port speed was 64000. What is this number? Where does it come from? What does it mean?
I'm confused. When my boss connects to the system his port speed is 9600 while he's connected at 56k to his ISP.

thank you,
konrad

[email protected]

This is still a mystery to me as well. Any help would be greatly appreciated.