Frankly this obsession with GPA if it comes out in your essays/answers will be detrimental to your application. Fact is your school will be submitting your official transcript to Penn (and other colleges). How Penn and those colleges recalculate the GPA, if they do, is not within your control.
If your concern is over how competitive your application is, fact is an A-<A<A+ for the same class. Colleges do look at rigor and if your school weights classes, an A- for a weighted class is likely > than an A or maybe even an A+ in an unweighted class depending on the weighting system.
While not Penn, take a listen to the Yale AO podcasts on the various aspects of the application. Inside the Yale Admissions Office Podcast | Yale College Undergraduate Admissions I think most selective colleges, including Penn view applications similarly. Focus your energy on things you can control.