What does 'get dinged' mean? It seems like this would lead to a strong incentive against making any changes, lest you introduce bugs, perhaps due to no fault of your own.

Yup. "Get dinged" was usually some kind of reprimand. It could go from being yelled at by the department manager, to being fired as a department.

And yes. It was a strong disincentive to making changes.

I didn't really like it, but our software did do what it said on the tin (which wasn't always ideal).