Bushranger

This is a timely thread as I was out for the first time with my newly purchased ORX today and struggled with any consisted ID of iron items. So much so I was wondering if I have received a faulty ORX! As an example one target gave a solid 97 in both coin fast and coin deep. Even with a 7-10inch plug gone and item still deeper with coil in the hole ..solid 97 and zero bars re probability of iron. Digging slightly deeper the mystery object was a large flat piece of iron plating. Even out of the ground the ORX is giving the plate a solid 97 and showing zero likelihood of iron. Is this normal, is there something I have missed or should I be concerned? Any help would be much appreaciated.