I wouldn't expect this. The only reason we know about that 500 number at all, or the percentage chances for items of different rarity, is because they are legally obligated to provide it.
Many reasons they scared so they hide it:
1. Legal issue/lawsuit: Guarantee 500.
If player reach 500 or more and didn't get it, customer complaint/ticket, or worst case, lawsuit will coming.
2. More pack sales
If people know they're too far from 500, they won't buying packs. By keeping it hidden, it will make people curious and curious people tend to gamble by buying packs.
3. Hide bugs
If there's issue with probability mechanism, no body will knows unless Respawn said so.
4. Hide the scam behind probability.
If there's scam where most people only get when above 450, no body will knows.
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