The manager is hopefully also a developer, and listens to his team Else you have a manager that sets arbitrary quality metrics that the dev team doesn't agree are useful then - and that's a way bigger problem.

In the case of contractor work where a customer actually buys the code and not just the functinoality - it's very tricky. I have never done contractor work so I'm not aware of how contracts are usually written. How do you set a quality metric? I'd be much more comfortable to agree to third party to judge the quality than to have an arbitrary metric in a contract for e.g. ratio number of comments to code lines, the average number of character in symbol names or the percentage of lines of code covered by tests.