Is it possible to cause water intoxication in cats by overly diluting their meals?

For my 11-12 lb cat, in total, he has been getting 13-14 oz of moisture (wet food +added water) daily. However, the recommended amount is 10 oz. So I have been adding 3-4 oz more than what he should be getting daily longterm. He has always kept a normal weight and activeness, however lately he's been having a lot of vomiting episodes, and we've been to the vet, so I am looking into everything.