First of all any extension to scheduled 100 hourly maintenance requires CASA approval. Ask the operator to show you that approval if he is trying to monster you into flying beyond the sheduled time. Secondly, be immediately suspicious of any maintenance release that is a clean sheet ie no recorded defects.
There are owners out there - often LAME's that own their own aircraft, who go ape if a defect is endorsed on their maintenance release. Regardless of how badly maintained the aircraft is, a clean maintenance release keeps the owner happy. One LAME in the Parafield area is well known for his habit of writing off a defect written by a pilot as "entered in error". Keeps CASA happy and stops pilots from writing up more defects as they know its a waste of time.