Bison - There was a thread on here a while ago that discussed this.
I'm not a paper collector, but I 100% agree with you - a note isn't a repeater unless something actually repeats! However, the logic is that if '9689' was to repeat, you would see those 7 digits. Technically, you could expand this to say 1234512 is a 5 digit repeater, 1234561 is a 6 digit repeater, and 1234567 is a 7 digit repeater. The premium stops at 4 digit repeaters though. I suspect it's to be consistent with the US.