I'm fortunate that my own company (Rackspace) at least has a level head about this sort of thing. My direct manager looks at my numbers (~60-80 interactions per month) and my colleagues (many hundreds of interactions per month) and correctly observes that we have different strengths, and that's the end of the discussion. I have a tendency to take my time and go deep on issues, and my coworkers will send me tickets that need that sort of investigative troubleshooting. My coworker meanwhile will rapidly run through the queue and look for simple tickets to knock out. He sweeps the quick-fix work away, but also knows his limits and will escalate the stuff he's not familiar with.
Let me stress here, this is not nearly as easy of a problem to solve as it appears to be on the surface. We're struggling as a company right now because after our recent merge, a lot of our good talent has left and we're having to rebuild a lot of our teams. Even so, I'm still happy with our general approach. Management understands that employees will often have wildly different problem solving approaches and matching metrics, and that's perfectly OK as long as folks aren't genuinely slacking off and we as a team are still getting our customers taken care of. I think that's important to keep in mind no matter how big or small your support floor gets.