Asymmetric calling card billing

[No gas will be sold to anyone in a glass container.]

Can someone shed some light on the following asymmetry in calling card
charges for calls between the US and Canada?

With an AT&T Calling Card:

Calls from US to Canada US rates and discounts apply
Calls from Canada to US Canadian rates and discounts apply
Calls within Canada Canadian rates and discounts apply
Calls within US US rates and discounts apply

With a Bell Canada Carte d'Appel:

Calls from US to Canada Canadian rates and discounts apply (!)
Calls from Canada to US Canadian rates and discounts apply
Calls within Canada Canadian rates and discounts apply
Calls within US US rates and discounts apply

The strange fact is that for calls from Canada to the US, Canadian rates
and discounts apply for both cards, while for calls from Canada to the US,
it depends which card you have. I've researched the tariffs and made the
calls, so despite the wrong information that AT&T and Bell Canada give out
regarding these calls, this is indeed the proper billing.
You might wonder what the Canadian rates and discounts are for calls from
the US to Canada. If I make a call from Madison, WI to Montreal, PQ with a
Bell Canada card, the rate is computed according to the distance between
the switching centers and the time in Madison, as if Madison were in Canada.
Bell Canada's discount periods (none on Saturday, for example) apply. More
often than not, this means the higher of the two countries' rates applies.
Perhaps someone can also tell us what kinds of financial transactions are
involved. Why do I pay Canadian tax on a call from the US to Canada if I
use a Bell Canada card, but not if I use an AT&T card? When calls are made
from the US to Canada and billed at the Canadian rates, who gets the extra
money?

Steve Kass No gas will be sold to
Department of Mathematics and Computer Science anyone in a glass container.
Drew University
Madison, NJ 07940 -Sign at a Santa Fe, NM
201-408-3614 gas station, January, 1985
sk...@drew.bitnet