Yes, those hours would be one off. You are also correct that Qhi on 660 don't have to teach eg Confined Areas. It does not mean that the QHI dosen't keep the skills set up during SCT, there is just no requirement to. The extra hours are to ensure that all QHI, regardless of Sqn or experience, are teaching CA's in the standardised manner and in the basic way- ie high reccie, low reccie etc. Slightly different to how it is done in the real world.