Asking "Am I being detained?" is useful for establishing the terms of a contact with the police, but repeating it every few seconds isn't particularly useful. Making it clear that you don't intend to have a conversation is much better. Then the cop can decide what he has and what he intends to do.
They don't usually tell you you're being detained if you ask. They just keep asking questions.
Then you keep asking "Am I being detained or am I free to go." If they want to play games just invoke the Fifth and STFU.
Asking "Am I being detained?" is useful for establishing the terms of a contact with the police, but repeating it every few seconds isn't particularly useful. Making it clear that you don't intend to have a conversation is much better. Then the cop can decide what he has and what he intends to do.