I'm not sure what your results actually tell you, other than that your D-76 wasn't totally dead.
In comparison to Kodak's recommendation for normally exposed Tri-X and freshly diluted (to 1:1) D-76 you:
a) added one stop of extra exposure; and
b) added 3/4 minute of extra development.
As the Massive Development chart includes data from a variety of sources, some of which may be suspect, I usually treat it with skepticism.
Your problem is that you don't know whether or not the age of the diluted developer resulted in a different result than if you had used freshly diluted D-76.
It would be just a bit inconvenient if you found it necessary to, each time, age your diluted D-76 for 5 days before it will give you your desired results.
In any event, I wish you the best of luck and lots of fun with this in the future.
One caution though - as scanning subjects are strictly off topic for APUG, you may get better results here if you leave those details out.
In comparison to Kodak's recommendation for normally exposed Tri-X and freshly diluted (to 1:1) D-76 you:
a) added one stop of extra exposure; and
b) added 3/4 minute of extra development.
As the Massive Development chart includes data from a variety of sources, some of which may be suspect, I usually treat it with skepticism.
Your problem is that you don't know whether or not the age of the diluted developer resulted in a different result than if you had used freshly diluted D-76.
It would be just a bit inconvenient if you found it necessary to, each time, age your diluted D-76 for 5 days before it will give you your desired results.

In any event, I wish you the best of luck and lots of fun with this in the future.
One caution though - as scanning subjects are strictly off topic for APUG, you may get better results here if you leave those details out.
Not a different question at all since that is the exact question I asked. Arrrgghh. Whatever.
Anyway, for those who read my OP and care Dead Link Removed with the following specs:
[*=2]RAW color scan from PIE XA and Vuescan using "Slide film" setting with no exposure lock or film base color lock.
[*=2]Inverted from negative to positive in LR5. No other editing. No cropping.
[*=2]Camera used is the Yashica Electro 35 GSN.
[*=2]Film is Tri-X 400 exposed at 200 ASA and developed in 5 day old 1:1 D76 at 20° C for 10.5 minutes. Full processing chart is here.I did some extreme bracketing; a sticky shutter released made me suspect a problem with the main switch assembly stop pad and one way to test it is with extreme bracketing. The resulting negatives indicate no mechanical or electronic exposure issues (user initiated ones were another matter).
In the future I'll use the exposure lock and film base color lock since it helps with consistency throughout the roll due to color cast caused by the film base. For the purposes of testing the D76 I wanted minimal post.
Perhaps someone will find some of this useful in some small way. Perhaps not.
Again, I really appreciate the well considered and topical insight.
here) is going to think less of you if you do use scanning for your own purposes.