AlexeevAV
I'm not sure if I understand you correctly.
I checked the save you uploaded and the Game Difficulty Mod doesn't seem to be active at all. There are no daily bonuses for AI from what I can tell.
What are the settings you made?

And let me explain: The mod offers two things that work independently from each other.
First there several options to strengthen the neutral stacks on the map, which you can choose at the beginning or skip completly if you press Exit. So no extra experience and faster development, if you skip.

Second, there is a option (activated by default) that strengthens the AI (all computer players) which can be disabled. The bonuses to AI are: stat points per level (like the script you requested) daily resources, daily experience and daily troops to all heroes. Please check readme for details.

Edit: And for the problem that the game gets easy after several weeks/month (especially in WoG) and you steamroll everything I made the Progressive Difficulty option which increases difficulty at a certain point (gameday) that you can define for yourself. Hope that helps.

Anyway: If you want to have the script active that you posted above just copy-paste it to an erm file, write ZVSE above it and make it as a mod, done