So, the formula says,

Take the "buildings:tank" ratio, raise it to the power of something, and multiply it by a number Q that increases slightly per special attack already made, and Q increases linearly with no limit at the rate of 1/$divisor. Then if the damage is less than 0.1, set it to 0.1.

So there is no maximum damage that can be done, only a minimum of 0.1.

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Without knowing what $exponent is (whether it is larger or smaller than 1), the

pow(ratio,exponent)

where ratio is the adjusted building/tank ratio, can result in just about any number between 0 and infinity.

Let's look at 4 cases from the smallest result to the largest:
ratio < 1, exponent > 1: Result < ratio
ratio < 1, exponent < 1: Result < 1
ratio > 1, exponent < 1: ratio > result > 1
ratio > 1, exponent > 1: Result > ratio

In the extreme case of 0 tanks, you end up with this on the first AB:

max(0.1, [($frontcut)/$divisor] * pow(($target_buildings + $addtop)/$addbottom, $exponent))

If exponent is a large number, that is only going to amplify the very large adjusted building/tank ratio, and you end up with ridiculous returns.