"Ultimate Damage"
-Can be obtained by making either a summon or a magic spell use animation for Highwind, then make it quadra-magic able
9999*81*4*2=6,479,352
Ultimate damage should come from when you're able to use a spell 16 times via 5x Quadra Magic and W-Magic/W-Summon. Be aware of this particular glitch, if KOTR is Quadra Magic enabled, then you could have the following: W-Summon, Quadra Magic + KOTR, Quadra Magic + KOTR, Quadra Magic + KOTR, Quadra Magic + KOTR, Quadra Magic + KOTR.
That's 9999 * 13 * 8 * 2 = 2 079 792 for KOTR. If you wanted to make it use the Highwind animation, then it'd be: 9999 * 81 * 8 * 2 = 12 958 704 (double of what your original guess was).
I'll explain the Quadra Magic thing, don't know if it'll help with the calculations (these are were made by observation on the PSX original NA version of FF7).
I'll make this a little easier for one of the things I'm going to use instead of writing out/copy and pasting Quadra Magic + (Spell) all the time.
- 1 Set = 1 set of "Quadra Magic + (Spell)"
- #Of times cast = the number of times the spell is actually cast during the battle when you actually cast the spell (duh).
- #Of times shown (Level XX) = the number of times that the spell is shown cast on the magic screen when you go Menu (Triangle) > Materia > Check > Magic > Select Spell. Then on the right hand side of that screen, there's a ratio that'll look something like "4x: 10x". The 4x represents the actual Quadra Magic materia. It is there by default and will never change. Then the number on the right side of the ratio is the number of times that the spell is ~shown~ to be cast, this doesn't actually tell you how many times the spell is cast in the actual battle (providing that your enemy survives the attack)
The "Level xx" represents the level that Quadra Magic is at. Different levels show different numbers. You should take notice to the pattern as the levels go up.
Chart:
--------------
=>1 Set (of Quadra Magic + (Spell))
# Of times shown (Level 1): 4 (usable once during battle)
# Of times shown (Level 2): 4 (usable twice during battle)
# Of times shown (Level 3): 4 (useable three times during battle)
# Of times shown (Level 4): 4 (usable four times during battle)
# Of times shown (Level 5): 4 (usable an unlimited amount of times during battle)
# Of times cast: 4
=>2 Sets
# Of times shown (Level 1): 5
# Of times shown (Level 2): 6
# Of times shown (Level 3): 7
# Of times shown (Level 4): 8
# Of times shown (Level 5): 9
# Of times cast: 5
=>3 Sets
# Of times shown (Level 1): 10
# Of times shown (Level 2): 11
# Of times shown (Level 3): 12
# Of times shown (Level 4): 13
# Of times shown (Level 5): 14
# Of times cast: 6
=>4 Sets
# Of times shown (Level 1): 15
# Of times shown (Level 2): 16
# Of times shown (Level 3): 17
# Of times shown (Level 4): 18
# Of times shown (Level 5): 19
# Of times cast: 7
=>5 Sets
# Of times shown (Level 1): 20
# Of times shown (Level 2): 21
# Of times shown (Level 3): 22
# Of times shown (Level 4): 23
# Of times shown (Level 5): 24
# Of times cast: 8
=>6 Sets
# Of times shown (Level 1): 25
# Of times shown (Level 2): 26
# Of times shown (Level 3): 27
# Of times shown (Level 4): 28
# Of times shown (Level 5): 29
# Of times cast: 8
=>7 Sets
# Of times shown (Level 1): 30
# Of times shown (Level 2): 31
# Of times shown (Level 3): 32
# Of times shown (Level 4): 33
# Of times shown (Level 5): 34
# Of times cast: 8
=>8 Sets
# Of times shown (Level 1): 35
# Of times shown (Level 2): 36
# Of times shown (Level 3): 36
# Of times shown (Level 4): 36
# Of times shown (Level 5): 36
# Of times cast: 8
Then just double anything with W-Summon or W-Magic.
EDIT: Oh yeah, about about that reflect thing... remember you can only reflect a spell 4 times then reflect is gone. You can't reflect summons either.
I also forgot about the thing you can do, use Mime + Quadra Magic and Counter + Mime instead and you can actually Mime Highwind 16 times providing it was the last move you did. Have a couple of Hero Drinks and you've got something.