[2023] Retro artifacts on arena have a lower drop rate then in paper and this isn't documented

I had assumed that the upgrade rate for retro artifacts would match that of paper packs, where there is a 34% chance to get something other than an uncommon. However I contacted support about this and found out that the upgrade rate is only 20%. Note that this is not listed on their drop rates page (https://magic.wizards.com/en/mtgarena/drop-rates). I feel like this is not sufficiently transparent and misleads people into thinking they would get more out of their packs then they actually do.

How do you feel, should there be more transparency on lootbox mechanics where drops are random? Did anyone else feel short changed on their retro artifact drops?