Credit consumption reduction is based on Basic unit credit consumption Commander.

Other features do not count.

I mean, what's the mathematical formula for it. I understand that it reduces basic unit credit consumptions, but how is it calculated? That was my question.

Contact Support Commander as I am not alowed to share that info.

Use this link to contacte them:

Plarium Support Center  

I see. I'll try to figure out the formula myself. Thanks for the replies.

You are welcome Commander and keep enjoying the game~~

There are multiple categories, bonuses within each category are added together, but then the reduction between categories is multiplicative.  Ie if you had a 30% reduction from items and a 50% reduction from buildings, the remaining consumption from each would be multiplied together.  So 1-0.3=0.7 and 1-0.5=0.5, your final consumption multiplier would be 0.7*0.5=0.35.  I don't remember how many categories there are or what bonuses fall into each, it's been years since I worried about credit consumption haha.  

Thanks. That explains it. I was not able to figure it out. Kept applying different approaches.