I'm not sure your math there on the birthday paradox is right (you only check the time during a single 10 minute range every day, no matter what? and you wouldn

I'm not sure your math there on the birthday paradox is right (you only check the time during a single 10 minute range every day, no matter what? and you wouldn't look at it out of curiosity or for the pleasure of seeing a new quote?), but 15 days to the first collision doesn't seem like that long to me, for a piece of furniture that one would expect to be good for years to come and which costs $200+. And note that the number will go up rapidly from whenever the first expected collision is: only 10 quotes per minute means you're going to see a lot of duplicates after a few hundred days.