When land is taken by eminent domain under the provisions of the general statutes or any special act, and local real estate taxes are apportioned by the condemnor as of the date of condemnation in a manner differing from the common custom, method or practice in the town where the land is located, and the condemnor’s manner of apportionment causes the condemnee to bear a greater share of the local property taxes than would be borne by the condemnation and taxes had been adjusted according to the common custom, method or practice in the town where the land is located, that sum which is the difference between the condemnor’s computation of the condemnee’s share of said taxes and the computation of said taxes as made according to said common custom, method or practice shall be an element of damages in computing just compensation to the condemnee.