Tomcat - the CAA requirement to be either, sat next to a push out window OR be equipped with proper breathing equipment is designed to force stakeholders to address the safety equipment for offshore PAX.
If the Oil Companies and Operators decide simply to mount more flights, and therefore increase a perceived risk in doing so, it is juxtaposition to the overall goal. The seating restriction is, in effect, an alleviation to reduce risk to passengers in the short term allowing the Operators the time to research, source and procure better breathing equipment.
The UK CAA investigated the differential between both NS sectors. They could not identify any real differences in the Operations. Bear in mind the Helicopter Companies operate on both sides of the divide. However, this assessment continues by many stakeholders in an attempt to find something tangible that might make a difference.
I agree though with you that all of this, although essential, is secondary to the requirement to do everything possible to stay out of the sea.
Hope this helps.