How accurate are tools like the VA Disability, Home Loan and Housing Allowance calculators?

Disability and housing allowances are usually pretty spot on, depending on which one you use. Home loans, though.... WAY to many variables. Most people think a VA loan comes from the VA and one is the same as the next. Not at all true. VA simply guarantees the loan, it still comes from a bank, and banks can do all kinds of things with rates and fees. *If* you find a comprehensive loan calculator that allows you to input multiple variables - fees, closing costs, rates, points, down payment, zip code (to calculate taxes), insurance premiums - then it will probably be pretty close. But *any* home loan calculator that allows for all of those inputs will be accurate, it has nothing to do with VA loan.

I have never heard of a VA disability calculator