Your upload speed is pretty much at the limit for 4v4, let alone 5v5. You are probably borderline for 3v3 because you have something else sucking up on that upload.

The behavior you are experiencing is a clear lack of upload bandwitdth once the game starts.

You need to either :

1) Do a complete check of your computer to remove unnecessary programs sucking that bandwidth

2) Upgrade your line

3) Don't play more than 2v2

Your upload speed should be just fine (assuming no background internet usage) for 5v5.  It is low, yes, but it should work.  My speeds are around what you are showing, and I dont have issues, even with 4v4.  I can also attest to the fact that the new patch did indeed decrease the required bandwith, so 5v5 game should also work.

Is anyone else on your network.  At my place, there can be up to 3 computers on ym network.  If there is more than just me using the internet while playing Demi, My ping will spike like crazy.  This is becasue Demi uses the majority of my bandwith, so there is none to share.

Your edit in the OP made laugh and reminded me of my exact problem.  Theres a pretty long on-going thread about (what I think is) this same problem on Dead Ghost's post here http://forums.demigodthegame.com/352593.  Might pick up some tips from there.  Good luck!  

I have almost the same upload speed and cause 0 lag in 5vs5s. Although once or twice a week in a game of any size I will spike for like 15 seconds, then be fine for the rest of the match.

So I suspect that isn't the cause