The problem is that you’re stating that the plate umpire has authority where they do not, quoting rules that do not apply or exist. That’s where you’re creating a lot of confusion among players who are reading this thread.
The USA/ASA Rule Book is "THE OFFICIAL PLAYING RULES" . Below is the section of the RULEBOOK that refers to the responsibility of the plate umpire during game play, cut and pasted directly from Section 10 - UMPIRES and i have highlighted and underlined the single most important sentence in Section 10, POWER AND DUTIES
"RULE 10 - UMPIRES
SECTION 1 - POWER AND DUTIES
The umpires are representative of the league or organization by which they have been assigned to a particular game and, as such, are authorized and required to enforce each section of these rules. They have the power to order a player, coach, captain or manager to carry out or to omit any act which, in their judgment is necessary to give force and effect to one or all of these rules, and to impose penalties as herein prescribed, The plate umpire shall have the authority to make decisions on any situations not specifically covered in these rules. The following is the general information for umpires."
This sentence applies to the entire Rule Book, Rule 1 thru Rule 10. The responsibility of making calls in the field of play, which is NOT covered by any hard and fast rule falls under the responsibilities of the plate umpire. Nowhere in the Official Playing Rules is there any reference for a specific assignment of responsibilities for making a call, this lies under the authority of the plate umpire, period.
You continue to use the UMPIRE MANUAL covering MECHANICS and best positioning methods, etc, etc which are not RULES. Yes, they are very important for umpires to learn these basic positioning positions, ie angle to call runner, catch, foot position of 1st baseman as a clear example. Positioning the base umpire inside the base paths when the ball is outside the paths, positioning himself outside this diamond when the ball is inside to negate the possibility of interfering with the fielder. Hustling to get into position to call a bang, bang sliding call with proper angle, stopping in time to position himself, seeing the call, selling the call when needed by asking the fielder to "show me the ball" etc, etc and my all time pet peeve, when a plate umpire calls out "fair ball" when he is only to signal with the inside arm toward fair territory and only verbally calling our "foul ball", how much confusion this umpire causes.
OK, so i have stated the basis of all of my posts for this discussion based on a printed rule in the Official Rule Book, not on the Umpire Manual which is a very useful guide for umpires to use for mechanics, positioning, etc but does not contain a single rule. The rules of the game are solely contained in the Official Rule Book.
So if the plate umpire instructs the base umpires before play starts, "I have the catch or no catch call on all fly balls, line drives, and pop ups" then that is the way that game will be called. If he states, "I have the catch or no catch call on all fly balls or line drives in the infield, base umpire has call on all fly balls or line drives in the outfield" then that is the way that game will be called.
The rule book defines the responsibility thru the plate umpire, the umpire manual helps all of the umpires to position themselves so they may effectively render a fair and equitable game for both teams by ruling on out/safe calls, fair/foul balls, catch/no catch situations and interpreting the rule book, applying and defining the rules and their effects, and explaining, when necessary those decisions to the participants.
I find nothing that trumps Rule 10 - Umpires, Section 1 - Powers and Duties