You can try to tune around a little.
Let's assume you have 100 K bandwith. You want to give uploads 45%, downloads 45% and connection communication 10% (you need this to keep up a couple of connection maybe 5-7 when you have lower bandwith then you should only maintain fewer connections).

Set up the following Phex configuration:

Network Setup-My Host Speed: 100 K
Download Setup-Max Bandwith: 45K
File Sharing Setup-Max Bandwith: 45K

This should maybe improve things in my opinion.
There need to be improvements done in this area. So I'm happy if you all can provide us with more experience reports.