Yeah, it depends how detailed you want to get with it. You could look at the efficiency of the unit in both cooling and heating, and estimate how many hours/days of the year you would run the unit in each mode. Then use your electric rates to calculate the costs. Comare it to a similar system to see if you are saving money.
One of the advantages of these variable refrigerant system really only applies to larger structures, where you have two spaces requiring different needs. One needs cooling (think of an interior electric room) and another needing heating (room adjacent to exterior). In this scenario you take advantage of the systems ability to shift the energy from one space to another without increasing your electricity demand.
There are other benefits, which include the reduced need for large ducts in the buildings, however, refrigerant piping is also expensive to install. It also has potential concerns from an environmental standpoint if it leaks in the building.
