It can't easily be described by a constant so it has to be a term batchSize^0.1. Probably this should be in the describtion instead of the tooltip.(it is now)
In the Han CC i changed 0.8 * 0.75 to 0.8 - 0.2 so it could also be described the same way. In vanila 0ad the final value didn't change (it's still 0.6) but in a mod which multiplyes the modifier by another factor it might change.