NOTE: This answer relates to a rule proposed by REC and does not reflect current regulations in effect:
A restriction only applies if the translator was originally mutually exclusive in the filing window and the status as a priority fill-in translator was a factor in the grant. In that case, during the first 4 years of licensed operation, the translator would be restricted from modifying into a situation where the new site's translator service contour receives at least 3 NCE services (including the underlying primary station) at any location based on the spectrum snapshot taken prior to the translator window. If the fill-in translator was granted as a singleton, but still qualified for priority, then this restriction would not apply.