Ok so I'm not 100% on the steps you need to take in order for this too work but I'll do my best to explain exactly what I did.
Also I'm not sure if people already know about this so apologies in advance if it's common knowledge.

Right so what I've noticed is when I open promo packs on my console 35k packs for example I opened 16 an was left with 4 an hour later I was on my companion app an noticed I had 10 remaining so I opened all 10 (got nothing as usual) but when I went back on my console I still had 4 remaining and was able to open all 4.
So I got an additional 10 packs & the same thing happened with the 100k packs a few days ago.

Anyone else experienced this ? I haven't really tested this method if you can call it that too see how many packs it's possible to get but either way an extra 100k pack or 2 is fine with me.
If anyone wants too test this out please post any findings you have it would be appreciated.