Computation of modification in other cases.

(i) Further situations (other than those mentioned in paragraph [7] of this subdivision) may arise where gains are included in Federal adjusted gross income from disposition of property acquired prior to the effective date of article 22 of the Tax Law. In each of such instances, reference should be made to the applicable provisions of former article 16 of the Tax Law (including sections 353 through 359 thereof) and to the regulations promulgated under former article 16 of the Tax Law (including parts 266 and 267 of such article 16 regulations, which were formerly articles 487 through 493-1 of such article 16 regulations) to establish whether the property disposed of had a higher adjusted basis for New York State personal income tax purposes, on the termination of former article 16 of the Tax Law, than for Federal income tax purposes.

(ii) Taxpayers who own property which they acquired while former article 16 of the Tax Law was in effect, and which had a higher basis for New York State personal income tax purposes than for Federal income tax purposes when article 22 of the Tax Law became effective, should retain such records as may be necessary to establish this difference in basis in order to justify a modification of Federal adjusted gross income if and when such property is sold at a gain at some future time.