Richard,
Just to try to extend /answer your thoughts, there is no bowing, its quite a true neck and the luthier has taken the saddle slot to its limit for adjustment. What I need is a luthier with another trick up his sleeve , as I suppose luthiers - in the same way as any craftsmen - there are some who can tackle normal problems, and, some who have a little extra to source and cure unusual occurences.
The average player wouldn't realise where I find fault and I repeat it is still an emminently fine guitar but ....but.......

Story time ..........
I still have 2 Nos Yamaha FG 180's circa 1971 which were a well made copy of the D-28. Yamaha made them really well to get into the market.
I had bought a Harmony Sovereign , and when I got it home from the shop I put on the brand-new strings the shop had provided me as part of the deal. To my horror when I tuned it all up - and twanged a chord - the bridge pulled off the front of the guitar. The shopkeeper offered me the FG 180, and gave me some money back as it was less expensive than the Sovereign.
I had many many years of pleasure from playing it,and I confess on occasions to not giving it the care and respect it deserved . A true workhorse !!Incidentally the 2nd one was bought not out of greed / possession - years ago a guy who was getting married offered it to me as he needed the cash and he wasn't such an avid player anyway.   

Incidentally,I don't know if I've got my wires crossed, but when you mentioned Yamaha CPX series - I assume you were replying to another message - you lost me with THAT reference - it's easy to lose me these days !!!.

Cheers Betsy.