The unit owners are bound to contribute pro rata, in the percentages computed according to G.S. 47A-6 of this Article, toward the expenses of administration and of maintenance and repair of the general common areas and facilities and, in proper cases of the limited common areas and facilities, of the building and toward any other expense lawfully agreed upon. No unit owner may exempt himself from contributing toward such expense by waiver of the use or enjoyment of the common areas and facilities or by abandonment of the unit belonging to him.
Provided, however, that the common profits of the property, if any, shall be distributed among the unit owners according to the percentage of the undivided interest in the common areas and facilities.