What? Neither of your conditions are necessarily true, and they hardly make any mathematical sense. They are basically the exception to the rule, but would be hard in real life to do. Loan payback terms can be short or very long in either program, that is your choice and can change it anytime. With refinancing, unless you chose on purpose a program length so long that it accumulated more interest, it would be very difficult to pay more interest. Its just the simplest level math and wholly apparent during the process. In fact your totals, term, etc...is all right there to see before even committing, or you could use excel.
Not all loans are federal and their "amenities" arent that life changing. Unless you're going for a PSLF type thing, refinancing makes 100% sense. What does refinancing have to do with a credit report/score? I've refinanced 3 times this year, bought 2 houses and my score just improves.
For details that are less prescriptive and more in reality visit WCI, learn all about the pros/cons, etc...dont just take someones word for it.