Vexing Waxhaw question: Broome vs. Broom

My second in a series of basic unanswered questions about Waxhaw. (Here's the first.)

Any one know the reason the green street signs spell it as "Broome Street" while the white street signs spell it as "Broom Street?" Did someone get a deal on a misspelled signs or is there some historical explanation for the alternate spellings only a block apart?

The Town of Waxhaw appears to think "Broome" is the proper spelling based on the address on their website. Which to me is at least a little strange as I would've put money on the fact that the town of Waxhaw was responsible for the white street signs featuring the "Broom" spelling.

Any ideas? This issue obviously has massive implications regarding the name of this blog.