The IKEA website says Detolfs have a max load of eight pounds per shelf. I don’t know the exact weights of those figures and their stands, but I seem to recall hearing that War Machine MKI is about 3 pounds. If I had to guess, I would guess you were getting pretty close to the limit. You could always weight your figures.
Personally, I would not put three die cast Iron Man figures on the same shelf. I am very cautious about this sort of thing, as I’ve seen heartbreaking examples of overloaded Detolfs destroying collections. I’ve never heard of sixth scale figures causing a Detolf to break, but anything could happen with enough weight.
I always kept my Iron Man figures on the bottom shelf. Recently I set up a Klingsbo, which claims a max shelf load of 55 pounds, to house my Iron Man figures and my Gladiator Hulk. I find the 55 pound claim difficult to believe, but as long as it’s a little sturdier than the Detolf, it should be adequate.
Like you, I wanted to display my WM MKI and IM MK VI together, and the only way I could do that and sleep soundly was by buying a sturdier display. That might have been unnecessarily cautious, but who knows. If you do want a Klingsbo, they’re fairly cheap.
