When making a deposit in a different currency to the trading account it states "When using a conversion of the company has the right to withdraw funds from your account at the same rate at which deposit happened."

Can you tell my why the company adopts this policy? It seems unfair and creates a very high risk for the client.

For example, if my local currency was Australian dollars and my trading account was US dollars. I could make a deposit at InstaForex and then one year later make a withdrawal. In one year the currency rate could have changed a lot. This could result in a big loss for the client when withdrawing the funds.

Why doesn't the company process withdrawals at the current market rate for currency conversion?