On my last run I got a 1 acre land grab. Twice, on two different empires. I was using Drive on both empires with 10,000+ land. QMT code had attacks being 0-7% rng with minimum of 1 acre being taken if successful. So 1/700 possibility of 1 acre.
Was wondering what the formula is for Redwall.
Hm.
So Drive gives a 1.1x modifier
The land loss calc is:
$loss = mt_rand(1, ceil(($enemy[$building_type] * 0.07 + 2) * $modifier));
So if the enemy had 10,000 acres all in huts an attack has a chance to take between 1 and 772 acres. The Drive modifier is applied to the max possible, not the amount taken (...I'd make an argument for it being applied after the calc, but I didn't write it).
Basically the same as QMT, RNJesus was not on your side.
Drive on a 10k empire would have a possibility of being 1-772 acre grab. It simply increases the range of RNG. I understand now. Much obliged Windy.