Check your lease agreement and see what it says about the payment of fees. Most say that 100% is due within 14 days of the service charge demand so the company are facilitating you by allowing you to pay by SO. Tracking SOs is a very time consuming job, especially in larger developments so it's possible that the agent is passing on the cost. The other disadvantage is that some companies (like some insurance companies) charge extra if you don't pay the full premium up front. If everyone pays by SO, the insurance cost will go up.
However, most directors I know are going out of their way to make it easier for people to pay right now so if you have a word with them, they might be able to do something about it.