So I play with Drasca and a handful of other people at times. He was saving up 15 million to dump into 300 expert packs. He got to it last night and did a live twitch opening with myself and Xen13 hanging out in discord. Here's the raw footage:
https://youtu.be/E1diUUJkZTY
There's a reason it's so long. There's a couple of gold matches at the end to test the theory a final time.
The Pattern: It would appear to be that UR cards have a flat 10% chance to drop in every expert pack, but there seems to be a protocol where the game checks those drops and if you've gone 9 packs without an ultra rare, the 10th pack Will contain a UR card guaranteed. However, if you get an ultra rare from the 10% RNGsus, the system resets. So you aren't promised one UR every 10 packs plus whatever in between. But you do get at Least one every 10 packs.
We didn't notice this until about half way in and I didn't feel quite like going back through and documenting at what pack exactly a UR dropped, so anyone who wants to help us double check the numbers, feel free. But it felt like it was about the same in the beginning, we just didn't notice until later.
But this was a pattern that was called too many times to be coincidence. He ended up calling like over 10 ur drops at instances of the 10th pack out of a total drop of 33/34. He was 100k away from another "10th" pack, so we farmed two more gold games to test it again and also to test if it is dependent on consecutive pack openings through saving or if it works the same way if you buy one pack a gold game.
After I dropped the second game (thank you servers), I went ahead and bought some packs with money I saved to test the pattern myself. Got a UR on the 5th pack, kept buying to try to get one on the 10th, got a second on the 10th. So it worked for me too.
After the second game, he bought his final pack. Boom, UR card on the 10th pack since the last UR.
I'm posting this to hopefully help ease some troubled minds out there and to have the community test it out for themselves too and maybe post here about when/if it works for them as well.
Assuming this pattern is programmed into the other packs the same way, someone somewhere should be able to test this type of drop ratio in basic and advanced packs too in regards to getting uncommon and rare cards respectively.
As for premium packs, we aren't sure. But again, assuming the same kind of pattern for UR card slots, it might be the same: That each chance space won't go more than 10 pack openings without coughing one up. And that the UR space with the "higher chance" rate that's probably set around 15 percent either follows the same 10 pack threshold but at a higher percentage chance to drop each time, or it's upped to like no more than 6/7 packs before that one yields a UR to better reflect the higher drop chance. Further testing is needed, though because this pack has two UR chance slots, it might not be easy/possible to narrow what I just suggested as possible because you don't know which one is dropping when. Either way, many credits needed to figure it out.
Assuming this Expert pack/UR card chance/higher tier card chance pattern is true, and both Drasca and I believe it is, and I think others should be able to see it both for themselves and in the video... Then this is something that Bioware actually did right and I can actually applaud them for putting this in the RNG system. Maybe they do care. Maybe they do.
By that same token, to any devs this may come across: Don't change this. I'm hoping that sharing this in mass with the community helps everyone out at a whole and that the risk of them taking this out completely and just giving us all flat rate BS is not a risk at all. This is one thing you did right (or at least not wrong) in a huge pool of things you did wrong. Please don't screw it up by taking it out because of greed. Because of anything, really. This is one action that you've taken that actually lends itself to interpreting your behavior to your fans/customers as positive. And 1/10 can at least lend itself to a thin lined argument of livable. UR drop and dev action/inaction wise.
TLR
-Expert packs have a flat 10% chance to drop a UR, but also if you haven't gotten a UR by the following 9th pack after your last, the game will give you a UR in pack 10.
-Appears to not need to be consecutive purchases/saved and that the game just remembers the last pack. Further testing/community feedback needed for this assertion.
-Testing could be done to see if same drop rate occurs in basic and advanced pack with higher tier card drop chance. If not, this pattern may only exist after maxing rares. Both tests need input from not maxed manifests.
-Premium pack pattern currently unknown. Also likely more difficult to find as definitive of a pattern due to two UR card chances in one pack. Future testing/saving needed.
-Bioware: Don't fuck this up by changing this if you happen across it. This is a giant help to the fans/players and to yourself. Taking it away would be developer suicide for so many reasons.