Yes, there's a difference. But if you get it the wrong way round, it's not a big problem, you'll still be understood. Ideally, the first time you ask someone to repeat, you'll say something like "Can you say that again please?" or "Can you repeat that please?" But if you need yet another repetition, this is when you'll say "Can you say that one more time please?" or "Can you say that yet again please?" or "Can you repeat that again please?" So, the first repetition is the repeat, and any additional repetitions after this are repeats again.