Both are correct. Adjusting armor is not repairing it, it is modifying the armor for better use by a person it does not currently fit. They are two different uses of the Engineering skill with different DC scaling rates.
Whether Adjusting Armor, basically everything involving computers, and any other cases of a DC with +2*Item Level should be changed is an open question for the designers. It is entirely that none of them "should" be changed. And unless the designers say otherwise, that is implicitly the official answer.
That said, I would personally reduce them to +1.5*level for consistency, most likely.
I just don‘t get the logic behind the math.
Low level armor is easier to modify and harder to repair and later on,
higher level armor is more difficult to modify but easier to repair .
"This super advanced, highly customized armor practically repairs itself, but good luck modifying it for use by a Barathu."
It actually tracks somewhat. High-end gear is generally built to spec for one person, so it being hard to customize makes sense. Similarly, it is built into the lore that the armor has some self-repairing functions (as you don't depressurize as soon as you are shot while in space), so more advanced armor being a little easier, comparatively, to repair is understandable.
Personally I find the scaling of the DCs to be kinda ridiculous in general, but I'm not sure anyone really knows what high level Starfinder play is like yet.
Has anything more been determined on this? I just realized that a 20th level armor would require a DC 50 check to adjust... and after scrounging through everything I can find in the Armory and CRB, it turns out that a DC 50 Engineering check is rather difficult. Completely optimized with armor smiths tools MIGHT be able to take 10.. but most characters are rolling with 75% or higher chance of failure.
For that matter, how long does adjusting armor take? I could not find that either. Repair is 1 hour, but as noted earlier, is a different beastie.
DC50 to readjust literally some of the greatest suit of armour in the galaxy sounds about right. The complicated and advanced nature of the equipment should have a factor. Sucks, but thematically it makes sense.
Depending on the action, Take 20 could be useful. I was actually looking at the morphic skin magi tech... It would probably require adjusting armor to gain the full use of it, which means either using Shiftskin armor and two forms, or adjusting to every new form. 20 rounds, even 20 minutes, is doable. 20 hours would be less so.
Edit: If it is supposed to be the same as repairing armor, that doesn't allow take 20.
For that matter, how long does adjusting armor take?
I think I remember reading "10 minutes" somewhere, but I may be misremembering.