68 Pa. C.S. § 3313
Any amounts accumulated from assessments for limited common expenses and income from the operation of limited common elements to which such limited common expenses pertain in excess of the amount required for actual limited common expenses and reserves for future limited common expenses shall be credited to each unit assessed for a share of such limited common expenses in proportion to the share of such limited common expenses so assessed, these credits to be applied, unless the declaration provides otherwise, to the next monthly assessments of limited common expenses against that unit under the then current fiscal year's budget, and thereafter, until exhausted. Any amounts accumulated from assessments for general common expenses and income from the operation of the common elements, other than limited common elements with regard to which limited common expenses are assessed, in excess of the amount required for actual general common expenses and reserves for future general common expenses shall be credited to each unit in accordance with such unit's interests in common elements, these credits to be applied, unless the declaration provides otherwise, to the next monthly assessments of general common expenses against that unit under the then current fiscal year's budget, and thereafter, until exhausted.
68 Pa.C.S. § 3313