(a) When any notification of a pending tax sale or a tax sale subject to court confirmation is required to be mailed to any owner, mortgagee, lienholder or other person or entity whose property interests are likely to be significantly affected by such tax sale, and such mailed notification is either returned without the required receipted personal signature of the addressee or under other circumstances raising a significant doubt as to the actual receipt of such notification by the named addressee or is not returned or acknowledged at all, then, before the tax sale can be conducted or confirmed, the bureau must exercise reasonable efforts to discover the whereabouts of such person or entity and notify him. The bureau's efforts shall include, but not necessarily be restricted to, a search of current telephone directories for the county and of the dockets and indices of the county tax assessment offices, recorder of deeds office and prothonotary's office, as well as contacts made to any apparent alternate address or telephone number which may have been written on or in the file pertinent to such property. When such reasonable efforts have been exhausted, regardless of whether or not the notification efforts have been successful, a notation shall be placed in the property file describing the efforts made and the results thereof, and the property may be rescheduled for sale or the sale may be confirmed as provided in this act.

(b) The notification efforts required by subsection (a) shall be in addition to any other notice requirements imposed by this act.