It has been shown (various white papers, unfortunately, I do not have a reference). That higher concentrations of IPA, does not increase kill or efficacy of the IPA at all, and actually decreases efficacy (maybe due to JH-RYU’s comment). 70% is pretty standard and is super inexpensive and avialable from all sorts of suppliers. Agencies pretty much just accept it.
I wouldn’t spend the time or money to validate difference. Sometimes its not better to challenge assumptions, I think in this case just go with industry standards.