Damage Testing - Effects of Attack on Damage Dealt

Taken from a reddit post on what upgrading your attack on weapons actually does.  This is why I've been pushing to get my most commonly used stuff to 300 ASAP.  Makes a big difference against higher level enemies.

I have seen a lot of posts about this and wanted to do a fast test. I would like to do additional testing with more levels, but have not had a chance yet.

Tests were completed with two Proxima Centauri II Scout Rifles. One is upgraded to 300 attack and the other is still at 248 attack. No perks add to impact in any way so they are identical for damage purposes. The crit multiplier is 3x. I will stick with just the base damage to keep things simple. All enemies were red health bar mobs.
My character is level 28 during these tests.

Lvl 8 248 attack Scout 158 damage. 300 attack Scout 158 damage.
Lvl 9 248 attack Scout 169 damage 300 attack Scout 169 damage
Lvl 15 248 attack Scout 254 damage 300 attack Scout 254 damage
Lvl 22 248 attack Scout 272 damage 300 attack Scout 356 damage
Lvl 28 248 attack Scout 272 damage 300 attack Scout 356 damage

I will do some more testing with additional levels, but here are my conclusion.

Low level enemies
Each level of combatant has a damage cap based on impact. Attack will not affect damage to those lower level mobs. You can see that level 8, 9 and 15 all take exactly the same damage regardless of the attack of the weapon.

On level and near level
You can see that there is a pretty significant difference between the two weapons vs both level 22 and 28 enemies. The damage done by each weapon is the same for both levels, but the 300 attack weapon dealt about 30.9% more than the 248 attack weapon. Upgrading your attack will definitely upgrade your damage dealt at least up to 6 levels below you.

Future Testing
I have 2 different scout rifles with different impact ratings at 248 attack. I would like to add that to my data.
The 248 attack scout is almost ready for an upgrade to 257. I can then retest to add some more data points.
I would like to add some data for damage dealt vs yellow bar mobs.
I would like to find where the break point is for attack having an effect on damage (probably somewhere around level 18 or 19).

The biggest takeaway is that you definitely want to upgrade Attack even fighting on level. The idea that Attack only affects above level damage is definitely wrong.
Once i have better numbers I will drop them into a google docs spreadsheet to share.
Praise the sun!