post office nearest matching

I just got a letter in the mail that was addressed to (addresses obfuscated, but with the same patterns as in the real one):

Andrea Evans
22609 20th St.
San Francisco ...

It has a "Notify sender of new address" sticker on it, with my address:

Evan Martin
2496 20th St.
San Francisco ...

The post office must have done some sort of weird nearest-matching algorithm, because our names and addresses are vaguely similar...