Coffers vs. Armbraces?

Okay, I have recently turned into the DoA business and I am wondering what makes more profit for you? Because by my calculations:

15 gemsets = 15 coffers = 1 armbrace.

Now, armbrace equals to around 22-23e, 24e if you are lucky. That is around 165k, 180 if you are lucky. While coffers sell for 2e each and you have 15 that equals 30e = 225k. 6-8e difference is quite much to me.

Also the gem individual prices are said to be:
Tormented gemstone 2,5k
Titan gemstone 5k
Stygian gemstone 2k
Margonite gemstone 3k

Which equals to 12,5k/set. While Coffer is weirdly 15k. That's 37,5k profit if you are low on cash and just want to quickly turn around a bit of plats.

But here's the cache. I see a few coffer sellers every-so-while and they are there for quite some time. What I want to know is whether the coffers are selling a lot or would I just be making loads of coffers I couldn't then turn in profit?

Hard sales, imo people trying to sell coffers for 2e/ea are quite stupid and wasting their own time. If they spent all the time trying to make that tiny bit of profit actually doing DoA for example, they would make a lot more..

I always sell my own gemsets I get from DoA individually for ~13k/ea. I find that this goes faster and is more reliable than selling armbraces, although lately, armbraces started selling easier.

I once decided to turn in my 150 gemsets for coffers though, I calculated howmuch they would earn me if sold on the street, and then I calculated howmuch I got from the coffers, made about 400k profit. But, this was right after the Survivor update, when I sold my LB scrolls for 2,5k/ea in no time.. So, don't know if this still works.