The reason I ask for three blocks of time is because the Investor is WAY BUSIER than I am. SO, in this scenario, I'm giving him the option to basically PICK what time works for him and I will 99% of the time go with the first one.

I also ask for TWO more so that we reduce on email back and forth.

Its all about 1) less emails and 2) accommodating the investor. If he or she is already looking at the calendar for ONE time that works, sureley TWO more is not that bad and it increases the chances of getting a mutual time that works.