A happy spring time to you and yours!
We did the first prototypes with a combo of radii and parabolic curves a little after your 1994 VA was made. A while before that we just radiused the tall fingerboard transverse brace to keep the fretboard extension from diving in past the body joint. Because your VA shows this deformation, it probably pre dates that revision.
The first top with the complete parabolic treatment was a precurser of our D/PW, done about ’96-’97. I named it “Archy “and had every intention of keeping it for myself and observing how it changed over a few years. Alas, cash flow and pride effect my judgement and I “loaned” it to Dan Tyminsky in order to enhance our famousity while having him report on its progress. Alas again; the reports were not forthcoming and I heard much later from a guy who had bought it from Dan and then sold it off to parts unknown…dang!
The adaptation was so much of an improvement in sound and durability that I incorporated it into our standards of procedures for every SCGC instrument from then on. The durability and sound improvement come from the integrity of an egg shape being superior to that of a box when pressured from various angles while being a much improved air pump over a less efficient flat top.
The “drop off” of the fret board extension after the body/neck joint is exacerbated by diminished support when the brace is flat and by the difference in length between a 12 fret to the body neck and one that joins at the 14th fret. The same variation in the amount of drop off is also affected by the body shape, sound hole positioning and sound hole size. Among various guitar brands and ages in general, the drop off is affected by humidity which creates more, or less movement in relation to how well the top wood was dried, seasoned and stabilized prior to its construction.
Please bring your VA in for a check up and I will advise if we can mitigate your drop off to improve playability and intonation past the 14th fret.
All the best, Richard