Proxy auto-config (PAC) impacts ssh, scp, sftp

Question

Dear all,
I have this problem I am trying to find leads on how to understand and eventually solve it.
I am doing a lot of development under Unix. I'm spending most of my time at work on X11 (XQuartz) logged in on remote Unix servers using all "S" versions of standard protocols.  I'm under Snow Leopard because Lion is no good to my workflow (sorry to say this).
Since my employer has contracted an external company to filter all outgoing HTTPS traffic - and has updated the legacy proxy PAC file accordingly - I encounter huge latency problems with my ssh, scp and sftp traffic with my remote Unix servers : all "S" protocols are routed through the external company HTTPS filter.
I have created one Network Location (network sys prefs) that uses "Automatic Proxy Configuration" to point to the PAC file server (a).
I have create another Network Location that activates a distinct proxy setting for HTTP and the same for HTTPS protocols. I've set up as Web Proxy server the one defined as PROXY  in the PAC file (b).
Using (a) Network preference, all my ssh and scp traffic initiated under X11 is slow as a drag (10kb/s on a 100baseT full duplex to the server in the same building) because it gets piped through the external https traffic filter.
Using (b) Network preference, no problem at all with ssh and scp, and Safari can browse both http and https sites as per company rules.
My question is how can this setting of Network preference - combined with a PAC file - can influence a traffic that is secured through ssl but is not HTTP nor HTTPS ! 
I am looking for some documentation that would help me understand how Proxy auto-config is implemented in the network layer and if there are any recommendations I can do to my network team to fix their PAC file, perhaps, to restrict the proxy configuration to only http and https.
Any lead will help.
Thanks,
Thierry
The PAC file (stripped of restricted info). Note: The remote servers I'm working on are in the 10/24 IP range and a segment of a Class B my company owns.
function FindProxyForURL(url, host)
          var proxy = "PROXY XXX.YYY.ZZZ.1:80; PROXY XXX.YYY.ZZZ.2:80" ;
if (
          shExpMatch(host, "10.*.*.*")  ||
          shExpMatch(host, "192.168.*.*")
          return "DIRECT";
else
          return proxy;

Answer 1

Ooops. Sorry, I meant "10/8", not "10/24" IP range.