[ic] simple variable fetch for shipping mode cost

[Honest to Goodness]

Is it possible to make a shipping mode that simply grabs the value of
some variable (perhaps global) for the cost?

For instance, let's say I add a shipping mode like this:

CAN2	testomode	weight	0	0	e Nothing to ship!		{'ui_ship_type' =>
"weight",'ups' => "0",'PriceDivide' => "1",}
CAN2	testomode	weight	0	9999999	f [@@F2CAN@@]		{'PriceDivide' => "1",}

Will the checkout page grab the value of the global variable F2CAN and
use it as the shipping cost for mode testomode? And what about sessions?
If I have to use a global variable for this hypothetical scenario would
I be able to have different values for each unique transaction?

I'm trying to do a ups style fetch from a different shipper to get some
shipping costs. Where is the code that talks to ups and gets their
prices? Perhaps this would be easier and more elegant if I could clone
the ups system and adapt it to my needs.

So far I have a globalsub that opens a socket, sends out the package
info and receives a bunch of shipping options which I display on the
checkout page. Am I re-inventing the wheel? Are there already functions
similar to this built into interchange?