I really don't know where you are getting your math from.
7 participants should have a total of 28 UDP streams (2 video and 2 audio each) and two TCP streams each (for H.245). Add another two streams each if there is H.239, but H.239 works within the bandwidth envelope of the conference itself, so no added bandwidth. So I don't see how a 7 participant conference would have more than 42 unicast connections, 56 with H.239.
If the video streams are 140K and the audio is 56K you are looking at around 1.4M bandwidth before overhead. As most of that is UDP, there isn't that much overhead as compared to TCP streams.
And no, the 45 participants were all live, active participants. The MCU was in a data center, but the endpoints were all over the place, some over LAN links, some over DSL. And they were using H.239.