A 'but'?
I think this is one of the things wrong with GA.
Here is word from CASA that EO's aren't required for a specific thing, but, no, the STC isn't good enough, lets try and find a way where we can still charge the owner money for no benefit.
I have paid for a bunch of EO's in my time, and not once has the guy issuing the EO even been in the same state as the aircraft when it was being modified, let alone examined it himself.
EO's are a huge WOFTAM, and don't, in my opinion, do anything to promote safety. They do help the bottom line of some engineering companies though.
I am sure there are circumstances where an EO is warrented, like major modification of airframe, corrosion repairs, etc, but for something this routine, and for every LAME/Avionics shop I've spoke to, none had even had any thought other than an EO was required.
I am disappointed to think that places don't want to try to save their customers money, time and effort by even looking to see if an STC was available. There was another thread running about complaining that upgrades/maintenance by LAME's was costing more and value for money wasn't being achieved, and both sides made some good points, but why would anyone pay $600 to $1500 more for any given job, if they don't have to. Some of the posts made reference to the cost of jobs, and mentioned EO's. A lot of those posts/complaints/jobs have an STC. So why are we just accepting it, rather than challenging it?
It reminds me very much of the 5 gorillas in a cage with a ladder and a bunch of bananas story. Google it if you haven't heard it!