I explained earlier that the % increase from using two mods is marginal and can easily be accounted for via shards, arcanes, etc. The increase of adding umbral vitality together with umbral intensify, instead of just vitality I guess, is not something that is crucial. It is a "small" improvement at best, although having played for almost 2.2 k hours at this point I can say that Umbral vitality really is not worth it in most cases. The OP argument was that you have to have these, but that's incorrect. I am doing all content available in the game with one umbral mod or without any of them in some cases. You have other/better/cheaper options to get those stats. In most builds, replacing umbral intensify with intensify is not a significant deal at all. And as showed, you can have one umbral mod without umbral forma. For the rare cases that you want 2 or 3 umbral mods, well, feel free to dump the few umbral forma there. But this is definitely not needed nor recommended for all frames or even most frames.
You can easily test these things in simulacrum and you will see that the margins you are chasing are easily covered/exceeded by other means. Molt Augmented arcane can help, red shards can help, madurai focus tree can help, growing power aura can help etc... Same goes for armor and health, many other means to get those stats that will cover the margins umbral mods provide over the ordinary mods.