Usually, when donations promotions are done, the organization states and reveals (beforehand) how much of each dollar donated will actually be donated to the charities. If this is not stated beforehand, then the organization can adjust for "various" and "variable" expenses such as advertising. Unless the server is currently suffering fron lack of funds, it should have enough cash flow or cash assets to pay for these normal costs as uaual. Hence, the current statement of "actual donation = player donation - advertising - server costs" is as vague as it can get, since the server can spend expotential amount on advertising (variable cost) if player donation increases expotentially due to this promotion. As such, it would preferable to let players know that 90 cent per dollar will be donated, or X% of $1. When donations are involved, it is better to be clearer than vague since such promotions can be a conflict of interest between profit and charity.