Aaron,
When we lived in our duplex just about anybody would write the policy (State Farm, AAA Insurance, Farmer's, etc.). That changed significantly when we moved to a single family place and rented both sides. Maybe insurance rates are really high in your area, the place is super nice, or the company didn't understand it will be owner-occupied (or maybe that's a difference between duplex and triplex). Our dwelling fire policy on a 100 year old duplex in Minneapolis is ~$1500/yr. When we lived there (a few years ago) it was more like $1000/yr. I can see how risk goes up if the owner is not regularly present.
