p.s. I have just found something at NWN2 wiki:
In NWN2 (v1.23), the size increase from Enlarge Person is only a cosmetical effect. The spell does not actually increase the size modifier. This means it has no effect on Disarm and Knockdown rolls, and there are no penalties from increased size. The same applies to Righteous Might.
The "size penalties" are in fact a -1 penalty to Dodge AC and a -1 penalty to enhancement AB.
Is this possible to fix?