All right, guys. You ever notice how the stat growth rates listed for each character don't actually match the value your stats go up by, even without taking level bonuses and skill points into account? For example, Reimu gains 15 HP on her first level up, 16 on her 2nd, 18 on her 4th, and so on. That's because of the little-known value that I like to call the Level Multiplier. Unfortunately, I can't find any information about it. Here's the only thing the wiki has to say:
Furthermore, the multiplier goes up passively on level up even without any bonus investment on most stats (especially HP) but not SP.
With this in mind, I have tried to determine just what the Level Multiplier is, and to tie it in to the total stat formula. Here's what I've got to propose:
Your total stat is equal to:
(Starting Stat) + (Stat Growth * Levels Gained * Level Multiplier) * (1 + Level Bonus + Skill Points + Equipment)
Level Bonus = 0.02 per bonus given
Skill Points = 0.03 per skill level
The Level Multiplier is a latent additional multiplier to your growth rate gained for each level that's separate from your level bonus, so characters with faster leveling rates will benefit more than slower leveling characters. Its existance is not well-documented aside from a single line mentioning it on the wiki, as far as I know, but it's quite easy to see if you test it out yourself, even if it can be difficult to measure. However, the thing that's really interesting about it is that its value is different depending on which stat you're looking at. It's also why the actual amount of a stat you gain per level up doesn't match the growth rates (for example, Reimu has a listed SP growth rate of 20, but it only really increases by 2-3 points per level if you have no level bonuses or skill points). If you level a character from 1 to a much higher value in one go, you'll notice that you gain more stats per level the higher you go, even without skill points or any other bonuses. That's the effect of the Level Multiplier.
I can't say I've measured it down exactly, but after running some tests with my higher level files, here are my estimates for the Level Multipliers for each stat:
HP: 1.20 + 0.03 per level
SP: 0.125 (this value never goes up regardless of level)
ATK: 1.10 + 0.02 per level
DEF: 1.10 + 0.02 per level
MAG: 1.10 + 0.02 per level
MND: 1.10 + 0.02 per level
SPD: 0.0225 + 0.000645 per level
I'm not going to bother calculating it for EVA. SPD was a pain to figure out, but luckily I had a file with characters at level 500+, so I got to use some very high levels to compensate for the low amounts by which SPD tends to grow.
Now, I think this is extremely significant beyond helping you more accurately calculate your total stat. Why? Because this affects the gap between characters with high stat growths and low level rates versus those with the opposite situation. Consider this experiment with two characters that lack equipment, skill points, and level bonuses: Suika and Mystia have ATK growths of 16 and 10 respectively. Going from level 1 to level 2, Suika gains 17 ATK while Mystia gains 11 ATK, so Mystia only gains about 63% as much ATK per level as Suika does. However, this ratio doesn't remain the same throughout the game! Using the exact same amount of EXP for each character, Suika can reach level 475 while Mystia reaches level 547. That natural level difference produces a significant Level Multiplier discrepency between the two. At those levels, Suika gains 321 ATK on her next level up and Mystia gains 230 ATK. Now Mystia gains ~72% as much ATK per level as Suika does! The proportional difference between growth rates shrinks due to Mystia's faster level rate, even before adding in the extra level bonuses she gets. That's another reason why just looking at growth rates can be extremely misleading, as fast leveling rates can do much more than just give you additional level bonuses. They also give a small but significant latent boost to all stat growths (except SP).
I made my calculations using my 30F completed file (Team Unappreciated), which had a lot of characters that I never leveled up. For each stat, I chose a character with an even and easy number for their stat growth (usually 10), and documented their total stat at every 10 or 100 levels, then calculated the multiplier to their stat growth. If anyone would be willing to check my work and confirm my estimations, that'd be helpful.
