Ahhh Scott, pardon me for poking fun at you, but you are not truly accounting for the job, and this is why people go broke thinking they are charging enough?.but are not.
I hope you are not offended by my post as that is not the point. Too many folk expect everything for nothing, and they even expect that of Vans no doubt. Maybe it is a mindset thing but my point is even in ABE?.it is not as free as you might think.
No personal offense at all, and I hope that is reciprocal when I say that even though aviation is expensive (everywhere), with experimental aircraft we have some freedoms to influence the cost (if we choose to use them). Here in the states anyway. It sounds like you are quoting repair costs that would have been the same if it had been a certificated aircraft. That makes your charges only relevant for Aust., because here in the states (and other places), an owner doesn't have to use a certificated aircraft weld repair person. I also think of it as crazy to be paying shop rate for someone to travel two hrs round trip to do an inspection before the repair has begun (over here, the owner would pull the mount, take it to a shop that does specialty welding (race car fabrication for example) and get the job done with a quality that is equivalent to your certified aircraft welder at a fraction of your cost.
I am not naive about charging for this type of work. I ran my own business (successfully for a number of years) doing specialty work on aircraft (RV's and certificated).
The point of my original post (which probably wasn't conveyed very well) was that because of your rules being so different, your quoted cost is not a good bench mark for what this work should cost an RV-10 owner here in the states. If someone does pay a shop that much, my guess is that shop would not be doing to many more of those jobs.
It would be interesting to hear what the engine mount welding/repair charges were for the couple of other RV-10s here in the states that have required the weld repair. My guess is that it was a fraction of what you are quoting.