Think more subtly - if you need to meet a metric/goal of 50% of your time on phone calls and 50% on tickets, a manager who wants to tank your metrics will game

Think more subtly - if you need to meet a metric/goal of 50% of your time on phone calls and 50% on tickets, a manager who wants to tank your metrics will game the system to feed you less than needed to make your metric on one or the other. Just because a metric exists does not mean it's applied fairly or evenly to all employees.