Happens with first names, too. My wife's name is "Erin"-with-an-E, and she always gets asked "is that with an A or an E?" Really? How many girls are there named "Aaron"-with-an-A? Oddly, nobody ever seems to worry about the genuine multiple possible spellings of Erin/Eirinn/Eireann.

Nobody ever has problems with "Logan", though. I suspect it's just common enough that most people are familiar with the spelling and the pronunciation (thank-you X-Men), but sufficiently uncommon that almost nobody has ever encountered a weird alternate spelling that could cause confusion.