I have considered the idea of removing the neck and letting it sit for an extended period of time as TJH had suggested ...
Just to clarify, when I said this:
"... you could always try a switch to a lighter tension string to start with too as Zoober mentions ... or, take the tension off the neck for a few years, watching it every day, waiting for it to 'back bow like crazy', as your 'tech' suggests ...
.. I was being facetious ... you could stare at your neck everyday for a lifetime and chances of it fixing itself are slim to probably none ... it was probably a comment that didnt need to be made without knowing your tech ... washers or a mild fixture scenario, or lighter tension strings are much better options ..
