If no time limit is given by the manufacturer then yes you can push it to 250 hours - but if the manufactures maintenance manual says every 5 hours, then even under schedule 5 it MUST be done every 5 hours. It is not an option!
Connedrod yes 100.5 has been the bin, to put everything in to keep the things CAsA wont part with - that can not be included in the new rules. It is a mess.