You can only streetpass with a single MAC set every 8 hours. You COULD change the MAC set when you finish the first one, but doing so and cycling through all the MACs at once is kinda rude to others, seeing as they'll just keep getting you whenever they get that MAC.
I see! I've already fixed the connection problems I were having, and even though it is working fine now, I haven't been getting any streetpasses in the last minutes. By the way, I've gotten like 80 till now. Should I wait 8h to do it again or is it some kind of error?