SH [brandishing the claim form I have completed and printed]: Why did you put "18 Ave" instead of "18th Ave.?"
SH: But it's not right! We live on 18th Avenue, not 18 Avenue.
Me: So what?
SH: But what if their OCR system matches on the string "18th" instead of "18?" What you write has to match what's already in the system, which is "18th."
Me: I think they can figure it out. It's probably not the only time this sort of thing has happened.
SH: But it's not right!