I've had my brand new 2020 Prius LE for about 3 weeks now and it is only getting 47.7 MPG. Also, I am unable to find the "instantaneous MPG" indicator. I've run through the Display Setup options many times now and just cannot figure out where it is. My 2017 showed the MPG indicator right next to MPH and it consistently got 52.4 MPG. Only difference I've made is switching to 2020. Also no Navigation or SXM radio built in... all this fun for only $65/mo more than the 2017
Re: the MPG. We'd need a lot more info to know how to respond. When I drive my Prime in HV mode, I get about 55-60 mpg on the interstate and 60-70 in town. On the display, that's in the owner's manual. Just use the buttons on the right side of the steering wheel.
The 2020 might come with different tire brand. Also, new tires will always begin with lowered MPG until they "wear-in" Finally, check your tire pressures, and pump up to near the max cold allowed on the sidewall.