The posted odds won’t make sense once you start pulling, because they aren’t adjusted for pulls done. But that’s different from what you’re originally talking.
What you’re talking about is the quantity of items, having equal odds, not matching the supposed odds.
You’re thinking 21/60 items means that 35% chance to get a Y3 token, or simply, each item, regardless of what it is, has a 1/60 chance, or 1.66667%.
What’s actually happening is 0.7% chance for each individual Y3 token. (1/21 * 15%). Also, that’s not factoring in the fact that the 100 Y3 token pull is likely going to have lower odds than the 5 Y3 token pull.
So in reality, this is what the odds are for getting each item individually.
Y3 Token Pull: 0.714% -> 21 Y3 Token pulls = 15%
5* Token: 1.19% -> 21 5* Token pulls = 25%
4* Weapon Tokens: 3.3333% -> 9 Weapon Tokens Pull = 30%
Elite Item Tokens: 3.3333% -> 9 Elite Token Pulls = 30%
The odds above are simplified and does not account for the varying amounts of tokens that can get gained in pulls. So, for example, for simplicity sake, I’m assuming 100 Y3 token pull and 5 Y3 token pull share the same weight, within that 15% chance. Same applies to the other 3 token types.