Oh they all do, but often the rates are terrible (e.g. 1.5% commissions). I know IB has forex rates around what I can accomplish with less complexity, but it can be hard to meet their minimums to avoid monthly fees (especially with Canada's 'tax-free savings accounts').
Yes, normally, these trades heavily depend the currency pair, and the client, quantity, etc. And least that was the case at the bank I worked in the past