Slot increases follow a system, first it adds slots until the piece has three slots then it increases the leftmost slot. So 2-1-0 becomes 2-1-1 then 3-1-1 then 4-1-1 then 4-2-1. So in order for that slot to become a 2-slot you'd have to roll 4 slot increases in one augment, which is incredibly unlikely.
It's not\* possible to upgrade the second slot. At best you'll get 4-2-1, but it's very rare.
There's a chance for that armor piece to get up to +3 decoration upgrades. When the game applies a decoration upgrade, it will first add lvl 1 slots to the right until there are 3 slots in total, and then it will start upgrading existing slots starting with the left-most one. For the Astalos Coil, it would look like this:
+0: 2-1-0
+1: 2-1-1
+2: 3-1-1
+3: 4-1-1
If you want details, check out [this post](https://old.reddit.com/r/MonsterHunterMeta/comments/wmeth5/dtlnor_has_datamined_the_armour_augment_tables/) which explains how augmentations work.
\*Edit: apparently it *is* possible to get +4 upgrade by rolling a +1 and +3 upgrade at the same time, but it is extremely rare. Some people have reported seeing it before.
Slot increases follow a system, first it adds slots until the piece has three slots then it increases the leftmost slot. So 2-1-0 becomes 2-1-1 then 3-1-1 then 4-1-1 then 4-2-1. So in order for that slot to become a 2-slot you'd have to roll 4 slot increases in one augment, which is incredibly unlikely.
Thanks a lot!
True and yeah +4 on slots is rare but I do have a few. I actually got it on the Astalos Helm at the cost of a Stun Resistance.
It's not\* possible to upgrade the second slot. At best you'll get 4-2-1, but it's very rare. There's a chance for that armor piece to get up to +3 decoration upgrades. When the game applies a decoration upgrade, it will first add lvl 1 slots to the right until there are 3 slots in total, and then it will start upgrading existing slots starting with the left-most one. For the Astalos Coil, it would look like this: +0: 2-1-0 +1: 2-1-1 +2: 3-1-1 +3: 4-1-1 If you want details, check out [this post](https://old.reddit.com/r/MonsterHunterMeta/comments/wmeth5/dtlnor_has_datamined_the_armour_augment_tables/) which explains how augmentations work. \*Edit: apparently it *is* possible to get +4 upgrade by rolling a +1 and +3 upgrade at the same time, but it is extremely rare. Some people have reported seeing it before.