Max - PMA advice will change as soon as you get rid of seconds - if you don't believe that then you are being naive.
If 3:1 equals one 8 hour shift a day every year how do you square that with the fact we do a 24 hour shift? One crew on shift for 24 hours, one crew ready for the next day and one crew on leave/course etc. 3:1 seems to work until you add in FI dets and seconds so bin seconds and 4:1 would be the answer.
Mind you just how many courses are the SH boys and girls getting, not to mention leave - but at least they won't need pointless OOA dets as they are spending so much of their time OOA anyway!
The GOC had the other 12 lines of tasking to choose from if he wanted surge, plus AAC and RN aircraft. If all he had to do was provide SAR cover for NI and its environs, I bet he would have asked for a second standby crew.
The fact is that you interpret the SARF Cdrs data differently to him and I don't think he is about to cancel seconds - why is that do you think?