johnhc, no offense but I think you don't have any idea what are you talking about.
The guy is asking about Maximum unfinished simultaneous connections[TCP/IP patch] as you already mention, and for your information also known as half open connections. Also, ISP can not affect on this in anyway.
CODE
I just suspect that 50 is too large
This is way normal if you want normal connection. If you download torrents I would put even bigger value. Currently I'm using 16777215 value and I don't have any problems.
Now, recently Microsoft released new hotfix, which updates version of file which is patched with new value. Before this hotfix I did not have any problems with nLite, it patched file perfectly. For this new hotfix if it is integrated I can't tell if the patch is working, since I have not tested it yet.
Cheers