Xenon is a unique class. It uses 3 stats instead of the typical two that most classes do. Granted, daggers do follow a similar formula in which it's 1.3(4*LUK+STR+DEX)*WeaponAttack/100, but this class is new and definitely not a dagger.
M = Multiplier
A = Primary Stat, B = Secondary Stat, C = Tertiary Stat
The first problem, finding out what the primary stat is.
A regular level 10 Xenon begins with 20 STR, 20 DEX, 20 LUK. There are 5 Energy, which ends up in supposedly, 10% All Stat. Then with the link skill you have +5% all stat. The brace gives +2 all stat, ending up in 22*1.15 = 25.3 stat as seen in the screenshot. This could have also been (20*1.15)+2, and it's more likely the former.
The character has 11 blessing, the weapon is 18 attack for ATT = 29. Before we do any extensive calculation, it should be noted that Xenon's base mastery is 20% (28/144).
After leveling for a bit, we had become level 13 and added 5 AP into STR, DEX, and LUK in that order respectively.
5 AP Test #1
Based on these images, you can see that adding 5 LUK actually influenced the damage range slightly higher (12 vs 11 range added)
Since all things in MapleStory are floored, the all stat boost from the link skill and the Energy orb is actually the former (A+Boosts)*AllStat, because (25*1.15)+2 = 30.75, which is floored to 30. Compared to (25+2)*1.15 = 31.05 which is floored to 31 which is what is being displayed.
After leveling a bit more, we added 5 SP into Multi-Lateral and 20 SP into Incline Power. Multi-Lateral 2 would give 10% total damage boost if you receive 40 LUK/STR/DEX or more. Incline Power gives you All Stat, and as you can infer the purpose of this test is to see if passives would count for Multi-Lateral rather than it being a base stat.
As you can see from the screenshot, we haven't added any AP yet.
Refer back to the original screenshot given, we had 72 total avoid and the number was in red, stating that something was causing an increase in avoid. Weapon avoid is formally defined by the formula (Unless it has changed within the past year, though I doubt it did. Only thing that changed within that period is the way avoid itself works.):
Avoid = 0.2STR + 0.6DEX + 1.4LUK.
72 = (0.2(25) + 0.6(25) + 1.4(25))*X + 11 (Blessing)
72 = 55x+11
61 = 55x
x = 1.10x
Which means that Multi-Lateral would give you 10% avoid in the regular situation. Going back to the original image however, we see that after our +10 all stat endeavour from Incline Power, we have a total of 113 Avoid, or 102 without blessing.
102 = (0.2(42)+0.6(42)+(1.4(42)*X
102 = 92.4x
x = 1.10x
This concludes the fact that Multi-Lateral is not affected by all stat bonuses and is exclusive to the base of your stats only.
After leveling a bit more, we ended up going through the same 5 AP test again in the same exact order (STR, DEX then LUK).
AP Test #2
This followed a similar pattern, this time STR boosted the range by 13, DEX boosted range by 11, and LUK boosted range by 12. Since the difference isn't that big due to the nature of damage formulas being 4*A+B+C, meaning that it would take at least 4 of B or 4 of C to equal at least 1 of A gone missing. It would seem that the stats themselves are equal, leading to a damage formula of M*(4(A+B+C))*ATT/100 = MAX.
Putting this formula in practice, with our last screenshot we have..
M*(4(48+48+48))*29/100 = 276/1.1
M*(576)*29/100 = 276/1.1
167.04M = 276/1.1
M = 1.5
For several classes, a 1.5 Multiplier is normal. However, for completion sake, the Multiplier should there be a primary stat is as follows (it will end up being higher than 1.5 anyway due to the way math works):
M*(4*48+48+48)*29/100 = 276/1.1
M*(288)*29/100 = 276/1.1
83.52M = 276/1.1
M = 3.00
As you can see, having a primary stat will be much much higher than what most classes have as a damage formula.
To confirm my theory, let's go back and use the damage formula on an earlier screenshot that we used to prove that Multi-Lateral is determined by base:
1.5*(4(42+42+42))*29/100 = 219.24
Displayed is 240. 240/219.24 ~= 1.10x which reconfirms the fact that Multi-Lateral is based solely on base stat only.
For completion sake, I asked for one more screenshot with jumbled values.
Using the damage formula we conceived here:
1.5*(4(48+51+57))*29/100 = 271.44 * 1.1 = floor(298.5) = 298, which is true.
Damage Formula for Xenon:
Multi-Lateral does not take into consideration your all stat bonuses. It considers base stat only.
The All Stat% bonuses for Xenon are applied after all bonuses, just like potential.
That is all.
Credit goes to @Zelkova; for taking the SSes for me.
Rest goes to me for figuring this stuff out I guess.