chuckroast
Subscriber
And the various commercial packaging options all differ in small but not insignificant ways - so it can really help to know which version is being discussed.
There ARE differences, with Kodak having added stabilizers and sequesterants to make it possible to distribute it all in a single package. In later iternations, they may also have added components to try to keep the D-76 alkaline swings that develop over time with the mixed developer, under better control.
Troop and Anchell confirm that the openly available formula with metol, hydroquinone, sodium sulphite and borax (which don't need all the stabilizing and sequestering agents since they are not stored together but mixed individually) does produce somewhat different results.
The thing is ... it kind of doesn't matter. D-76 itself underwent a lot of evolution in its lifetime. The openly available formula is more-or-less how it started out. If people start mixing their own, and calibrate their workflow to it, they will get consistent and good results, every bit the equal of factory D-76. More importantly, D-76H appears to conquer the developer's notorious tendency to get rising pH over time. Moreover, mixing your own ensures that you're not bitten by the latest problem introduced by Kodak, Sinopromise, Adox, Ilford, et al when they decide to silently "improve" the product.
I have a lot of DK-50 and D-76 here as packaged by Kodak. But if/when I run out, I am not going to take a gamble on some other company's variation on the theme. As you point out, you don't know what you're getting. I'll just roll my own and adjust my workflow accordingly, thereafter certain that my developer will never change. I similarly plan to replace Dektol with D-72 when my stash of the former is gone.
Mixing your own is easy, fun, and cheap (assuming you know proper lab technique and use good bio-protection in the process) and more-or-less guarantees you're always getting the same thing every time. Thus far, I've done D-23 and Pyrocat-HD in glycol that way and have been very happy with the results.