Yes.
Describe the premises. Is it a house that's been divided into 3 apartments. Like basement, first floor, second floor? That would explain a single meter. If so, one think you might check on is whether the house was divided into 3 units legally. You can call the city building department. If it was done without a permit or in violation of building codes, you might have some leverage over the landlord's new terms.
It's hard to imagine a triplex designed for three apartments being built with one electric meter but I suppose it's possible. I don't know anything about Hawaii building codes.

