I gave this a try implementing the module. After about 4 days I had reports of PCs unable to get deltas from their GUPs. Basically I did the same thing except I made a 20 connection limit for the actual zip files so I could prevent to many GUPs from downloading zips at once. I think this inadvertently caused the GUP to not tell the manager that the delta was available so the PCs thought the delta wasn't available yet (if I understand how GUPs work). As soon as I removed the module the PCs updated.
I ended up not using the module and instead setup a second manager and told my GUPs to use it instead. If I could I would give it another try as I think the limit is what nailed me.
Keep in mind I have a 512KBps limit to work within for everything.
This is what I used which allows for layered bandwidth levels. If you decide to use this I would recommend not using "MaxConnection all X" option.
BandwidthModule On
ForceBandWidthModule On
Bandwidth all 112000
<Directory "../InetPub/content">
#
# MOD_BW Bandwidth Limiting
# 400KBps global limit for everything
# 20KBps limit per .zip download for file sizes of 1 byte
# Maximum connections set to 20.
#
BandwidthModule On
ForceBandWidthModule On
Bandwidth all 50000
<Files *.zip>
BandwidthModule On
ForceBandWidthModule On
Bandwidth all 350000
LargeFileLimit .zip 1 20000
</Files>
AllowOverride all
Options none
#Order allow,deny
#Allow from all
</Directory>