Our
rates are a lot more up-to-date than most other sources, and do not
include "buy" and "sell" margins. However, all others
things being equal, different sources can still quote different values.
Why? There are many currency markets all over the world, and like any
other market -- precious metals, for example -- specific rates will
vary from market to market. To continue this example, there are both
New York and London metal exchanges: their prices generally follow each
other, but are very seldom exactly the same. Which one is "right"?
Both. Generally, published rates are indicative only. There's no guarantee
you'll be able to get them locally, and they certainly won't include
your financial institution's buy-sell profit margins.