Maximum inputs for Industries

[mauried]

Many of the Industries in this game have a maximum value for the amounts of goods that can be delivered to them for the purposes of making something else.
Im trying to understand what the criteria is which sets these values as they seem to vary up and down frequently, and for no obvious reasons.
As an example I have 2 sawmills in adjacent towns which are both being fed with wood from the same forests and one consistantly has high input caps for wood of around 4000 or more, whilst the other barely gets over 1500.
Many other industries like steel mills or oil refineries do a similar thing, but the maximum inputs are always much higher and the variance is much less.
I guess that the behaviour is coded into the industry GRF , but are there external factors as well.
tnx

[2TallTyler]

Which industry NewGRF are you using? Vanilla and FIRS secondary industries don’t have any processing cap that I’m aware of.

[mauried]

Using ECS Wood Vector ver 1.2 for the sawmills.