There are methodical ways of valuating a private (and public) company. Some are pessimistic and some are wildly optimistic. Your can legally use whichever one you want, only you must only use that valuation method for everything. It’s illegal to value the company low for taxes and high for loan collateral. And if you sell it, you can owe back taxes if your valuation was off (sale price is the new valuation).
This is overly-simplified US accounting rules (from finance class 10 years ago)
I’m a mech E in the medical field. We’re consistently understaffed. If I validate an Excel worksheet in Excel '08 or a Python program in 3.5 with a specific version of NumPy, we’re probably sticking with those versions for a while. Every time I bring up re-validating with the latest version, keeping one old system running the old software requires fewer resources than me or a colleague re-validating.
My whole department is stuck on one version of Python because that was the most recent version when I had an emergency project and developed a data analysis algorithm. We validated it, then as new members were added to my team, they needed a copy, so we had to keep using it. I’ll probably re-validate it to the next Python release. It’s not only unit tests, or we could automate validation. Unit tests are a tiny part of validating software for making medical decisions. And software that directly runs a medical device (like firmware on an insulin pump) is an order of magnitude more rigorous than what I do.
Side note: there are people who somehow root their insulin pumps and run algorithms on them. There’s a group that can get a PID control loop on an insulin pump that has a more simple control scheme on it (because that’s how the FDA approved it). The company has been trying to get approval to use PID control in the US for years.