Since we are speaking of talent pool, I am guessing that anything North of 600V is a special crew. When a regular guy goes to adjust the trip unit on the breaker and realizes that medium voltage breakers have their trip unit mounted separately (protective relays) and are very specialized, or grabs a fuse puller to replace a medium voltage fuse, there will be an increase in labor (and medical) costs.
Just like special EC crew's for medium voltage, there are many PE's that are not familiar with medium voltage equipment and protective devices.
