Sorry, I don't speak Spanish .w. I'll try to translate what you're saying, but I'm not sure I got it right.
If I understand correctly, the first part is about the AT reducing the damages by 5% instead of 10% ? That's strange, on my hand it does reduce by 10%. Can you write me what values you're using ?
As for the second part, you're saying a difference of 150 between attack and defense gives 130%, right ? That is normal, you have to take into acount the base 20% absorption. So having a difference of 150 with 0 AT means you deal 150-20 =130% of your base damages.