if you are referring to a singular noun & possessive it should be consumer's interest(eg.) but if you are referring to a plural noun it must be consumers' interest. If you are saying it's your style, you don't have the right to speak about grammar. It's my style! 


There are thousands of language to be spoken on their own style. Considering an international language you cannot use your rule and style globally, use it at your home YOUR STYLE.