Doing general inbound customer support (not tech) for a telco for a couple of months, I had the opposite time-related experience. I had a low number of daily calls, and was occasionally upbraided for it. But when I got a customer, either their issue got fixed, or it got escalated to the next level[1]. They didn't have to call back unless there actually was work to do on their side. The usual experience was a couple of callbacks, as note-taking was seen by the couple-of-hundred staff as somewhat optional. A colleague of mine came through the same training process and was terrible for the customers - didn't know what he was doing, transferring calls to the wrong department just to get rid of them, never left any notes at all... but his daily call count was high, so the higher-ups loved him. Nice bloke, we'd go drinking together, but he wasn't who you'd want to get on a call.

[1] Arthur was the escalation point. I loved Arthur. I would go to him with a messed-up customer problem and he'd say "hand it to me, you don't have to worry about this anymore". I'd hand him the paperwork and I'd never, ever see the problem again (he actually did something with it, he didn't just bin it :) ). It reminded me a bit of the jedi mind trick: "You can go about your business..."