Now, such multiple rate differences occur between all other currencies as well so the financial community must have a way of dealing with it. Do the parties split the difference? If not, who eats the difference, the payer or the payee?
Even with organizations like PayPal who do huge volumes of these "cross-border" transactions, the rate they will charge for foreign currency conversions will change based on current conditions at the time and the rate may or may not necessarily align with the official exchange spot rates (e.g., those published on
http://www.ecb.int/stats/exchange/eurofxref/html/index.en.html ).
With bitcoin not being terribly liquid, order size is a big factor as well.
I think at this early point in the bitcoin economy, most services have taken the route of assessing a slightly larger than necessary premium against spot and/or have made the fee big enough to accommodate market inefficiencies where the bitcoin markets don't closely match forex spot rates.
A service that is doing fiat on both ends probably should consider bitcoin only as one of the possible routes. If a funds transfer route that travels through a pair of bitcoin currency markets offers the least expensive path (fees inclusive) then it goes through bitcoin otherwise it routes through other foreign currency markets. Unfortunately, the point at which the banking system intersects with the Bitcoin exchanges is something that differs so wildly from not just one exchange to the next but one bank to the next (e.g., Intersango UK bank might be slow or down, whereas Intersango's SEPA is functioning normal). This means each route has wildly varying fees, speed, volume limits, etc., that automating the routing process is harder than it would seem necessary.
But the consideration of bitcoin's exhange rate versus forex spot is something happening already on an individual level by consumers. Last month when the Euro buyers were rushing into bitcoin, there was frequently a 3% or more premium by selling your BTCs for EUR instead of USDs (after factoring for the EUR/USD exchange rate). So if a consumer found purchases that could be paid for using a SEPA transfer, the consumer chooses that route and as a result all the gain from routing the transfer through BTC was enjoyed by the consumer and not the seller.
There was some article about one of the P2P forex services, either CurrencyFair or TransferWise, I forget, where users of the service were praising it for helping them avoid the exchange rate gouging they previously had been paying for settling with a foreign creditor.
So it sounds less like there are actually businesses worrying about trying to be fair in offering exchange "at cost" but instead they are worrying about earning maximum profit from these international payments.
What would be nice to see start happening is some companies further up the supply chain start to accept bitcoins. That way if a company has let's say 2% of their revenues come from bitcoins, they simply route those proceeds towards their accounts payable with vendors who accept bitcoins and entirely avoid then having to convert revenues made with bitcoins into fiat each time.