Wow. So as soon as I took delivery I got on the freeway, set cruise control to 75, and drove 650 miles with just one stop. Is my car going to be scarred for life? Lol
Owners Manual, page 226, section 2-1, Driving Procedures; Breaking in your new Toyota First 200 miles; Avoid sudden stops First 600 miles do not drive at extremely high speeds avoid sudden acceleration do not drive constant speed for extended periods That's it!!!
I wouldn't worry about it. 75 mph is not "extremely high speed". Prius eCVT will not rev the engine at constant speed. I think that was intended for step gear transmission cars.