Someone else on my team purchased 5 chests and the odds of getting an adequate amount of elementium seems to have been decreased:

First chest: 10 elementium
Second chest: 10 elementium
Third chest: 20 elementium
Fourth chest: 10 elementium
Fifth chest: 10 elementium

This doesn't seem to match previous results. It's also pretty unfair when "10 - 200" is advertised. Were the chances decreased or was this extremely rare, horrible luck?

This is why I don't buy chests

They DID give you what they promised.

Every chest you purchased had between 10 and 200 elementium, didn't it?

It could have said between 10 and 1,000,000 elementium and you still would have gotten what was promised.

@boris that's the way the chests seem to work, buying doesn't improve your chances you just get more of the same. On almost all chests buy one, if you get a bad result don't buy anymore. If you get on a streak of good results keep going until you get a bad one then quit.
And it wouldn't surprise me if chances were lowered anecdotally;I had much better results and I saw many more big winners on social media the first few times these chest were offered and since very average to bad results like you got.