I'm taking my info straight from the ASA umpire manual. Look at the section that describes positioning and coverage for all the different possible runners on base scenarios. Then look at what it says the plate umpire should do on an infield ground ball with runner on first and second.
When you say "hold near the plate" are you sure they didn't mean go to the "holding area" (which is in foul territory, about 1/2 ay up the third base line).
When you say "hold near the plate" are you sure they didn't mean go to the "holding area" (which is in foul territory, about 1/2 ay up the third base line).