It's like a physicist laying out the math perfectly for an orbital launch, but then starts analyzing launch times using Astrology.
Very, very few investors apply valuation methodologies so well they they become true value investors, the name is really a marketing label for most funds. One necessary part of being a value investor that Buffett harps on in his letters is psychology, the ability to avoid bias in order to make decisions and not undo them in a panic. He works really hard to insulate himself from irrational fears, and focus on known facts.
For example, he tries to never know what a company's stock trades at when he reads their annual reports and start making his own estimate of it's value. If it's a great company and it's trading for $100, he doesn't want to be subconsciously biased to raising his valuation estimate just to justify buying it.
There is a great story from his partnership days. His partners were told up front he'd never discuss what they were invested in, he didn't want anyone front-running his trades at hurting the partnerships results. But one day during a market tumble a partner rushes in and demands to know if Buffett had invested in certain stocks that had crumbled. Warren just buzzes his secretary, asks how much the partner's share was worth, and told her to write him a check for that amount, and told the guy you're out.
He wasn't going to panic. He wasn't going to let others try to panic him.