Is there conclusive evidence?

 Spoiler

Reversing the formula, we get that he has
(855 *4,0 + 51) * 194 / 100 = 6733
watt = 673300/(855 *4,0 + 51) = 193,9786 -> 194 atk

Add in the 2 % bonus from mw and we get 870 str and 51 dex. Now, add in the 12 attack pot bonus:

(870 * 4,0 + 51) * 206/100 = 7273,86 attack

Assume multiplier last. Then, the max attack he'll be able to deal is equal to

(7273,86 - def * 0,5) * 1,4 * 1,5 * 5,5

Skeleosaurus has 810 wdef. Then
(7273,86 - 405) * 1,4 * 1,5 * 5,5 = 79335,333 max

Now, assume mults first:

(7273,86 * 1,4 * 1,5 - 405) * 5,5 = 81785,583 max

We see that multipliers first is the only possible option.

To prove it for other multipliers, use that method.