As a developer, I hate that attitude.
The developer talked to the user, decided they understand the problem, then written their understanding in stone for the users to bang their heads on.
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Side note: your users found the solution to this problem was offsetting your altitude by 2000ft at the start of your flight so that you can always work with positive values throughout the flight. It sort of works, most of the time, but will surprise you when you want to deploy new feature that reconciles current measured altitude with radar altitude with GPS altitude and with Google Maps. How typical technical debt.
This workaround does not cover the case if you find yourself in an emergency and so you could not have planned the offset beforehand. You will need to file a ticket requesting approval to change your altitude mid flight. You will have to explain to the approver the reason for this non-standard change and wait a week for the next CAB meeting to convene. I almost feel like working for a bank again.