Chest Protector Sizes and Throat Protectors

[Cubbies87]

For the upcoming baseball season, I plan on becoming certified to umpire High School ball. For the past couple years I have been working local games with the equipment they provide. However, I plan on buying a whole set of apparel and equipment for the new season. I did a lot of browsing (and reading of reviews) and for price and quality, and I'm planning on ordering the My100 package from +POS, plus a few other items.

But, I'm curious about the sizing information for the chest protectors. They say to have the chest protector reach just beneath the ribcage, about 2-3inches above the navel. Why is it placed so high? I know the chances of getting hit lower around the abdomen are slim, but why risk it? What are the benefits of having the chest protector cut off higher up?

Also, +POS describes their masks as having 2" extended throat protection. Is a detachable throat protector also necessary, or will the mask cover enough?

Thanks for the replies and the help.