The state in which expectations exist is known as the status quo. For example, if a person expects to pay 14% of their income away to taxes, the remaining 86% becomes the status quo of net income. When that changes, it disrupts the status quo and can cause possibly volatile results.
The solution would be to advertise or announce a recommended status quo, or RSQ. This dynamic works to set expectations at a specific level while allowing for that volatile range of results. For example, the RSQ for net income could be 75%. This allows for the majority to pay less taxes than they expect to, and for a smaller number of specific cases to pay more.