72 Pa. Stat. § 5020-307
The said township assessors and assistant township assessors and assistant triennial assessors shall make return, on oath or affirmation, to the county commissioners of the proper county, of the number of days actually employed by them in the performance of the duties of their office, and of amounts expended for postage, stationery, and office rent; and the county commissioners are hereby empowered to summon the respective township assessors and assistant township assessors and assistant triennial assessors before them, and examine them, upon oath or affirmation, as to the accuracy of the said return. When the county commissioners shall have determined, either from the returns of the township assessors and assistant township assessors and assistant triennial assessors, or from their examination of them as aforesaid, the number of days actually employed by them and the amount of moneys properly and necessarily expended for postage, stationery, and office rent, clerk hire and other expenses, the county commissioners shall make payment to the aforesaid township assessors, assistant township assessors and assistant triennial assessors the amount due them from the funds of the county as hereinbefore stated.
72 P.S. § 5020-307