It's true that if he said nothing he might have been taken to jail for 8 hours instead of being detained for 3.5 hours. But it's also possible that he talked and talked until eventually, under stress, he said something stupid that led to a conviction with a 2 year prison sentence. It's basically just a gamble with your life.

There's nothing wrong with being polite, but insistent on having a lawyer with you when you speak to the police. Tell them that you will be happy to talk with your lawyer present.

If the police are questioning you then there's an excellent chance that what they are really trying to do is to build a case. The more you talk, the more things can be used to make you appear guilty in court - even if they don't seem significant to you. That is why you don't talk to the police - even if it means sitting in jail for a day.

The concern that you might extend the length of your detention in the short-term is inconsequential compared to the possibility that your cooperation can and will be used against you. You aren't trying to manipulate the police into letting you go home earlier; instead, you're trying to avoid doing anything that may increase the likelihood of your being found guilty of criminal charges.

There are plenty of interviews online where police officers, lawyers, and judges alike can't come up with even a single example of where someone was able to talk their way out of charges. The popular "Don't talk to the police" video is just one of them. Hell, Salinas v. Texas makes it abundantly clear that you can screw yourself right into jail even when you do remain silent but make the mistake of appearing uncomfortable during questioning.

In short, there are just too many opportunities for even an intelligent, innocent person to stumble straight into jail.