Well, from what I've seen, everyone deals with this differently.
some at par, some US, some half and half, some fixed rate....
I'm pushing for fixed rate for Phi Sig...their biggest concern about this is that it might not cover costs, but hey, we're only 2 chapters out of 110! Also, for awhile they thought if we paid less it'd be unfair to U.S. sisters (that's when we had to explain to them the whole exchange rate and standard of living thing...)
Money was the main issue when I joined...I loved the women and the group but I was on student loans. I decided to go for it, and of course have never regretted it.
as for payment plan, i know we offer it for local dues, but International dues have to be in by Initiation(in order to get permission).