Sometimes a persons role in an organization might change but that doesn’t necessarily mean they are more or less valuable than before.
In soccer, it’s not unusual to see a player change position and while their stats might change dramatically (if they go from a forward position to a midfield position they most likely wont be expected to score as many goals) this doesn’t mean their value has changed as well.
To continue with the soccer example, someone who scores one goal every two games would be considered very valuable. However, if his team is losing most of their games and by switching his position and responsibilities he then scores less but it results in the team winning more, than his role might result in him being even more valuable despite the statistics.
Metrics are a nice thing to use to measure productivity but realize that different metrics should be used for different roles.
Have a great day!