I'm going to answer your concerns and comments in order:
You say I should be in "B", and I was. If you've never asked for assistance while in "B", I seriously doubt if you've umpired. Around here, if you have R1 (I'm in "B"), why does the PU come running towards the mound? To be able to cover 3rd, and see the play at first. My OP said "alotta dust". Kinda makes it hard to see sometimes. I cover ALL pertinent "what if's" in the pre-game. I always say, since it's happened to me, "if I ask you - don't signal out ... just answer my question". I already stated that R3 had crossed the plate. Your bottom line is not mine, nor anyone else in the Chicago or Illinois area. If you're not sure, ask for help. It is rare, but it happens.
In response to my OP, it seems many are interested in lessening the heat, and making a call that is sold. Don't get me wrong, I sell it. But I collect a paycheck for this: knowing and applying the rules and making good judgement calls. I never get into what's popular. Case in point: (I'm PU) last fall in a JUCO game, R1 and R3, 0 outs, 9-9 bottom of 10. Grounder to F4. Catcher is on top or slightly in foul territory (1st base side) of home plate. He gets the throw from F4 when R3 is about 2-3' away. Catcher puts the glove straight down (he must have forgotten where he was) and waits for the slide. R3 touches home first. Not popular. The visiting coach instantly became the Tasmanian Devil. I've been doing this long enough to know what the response was going to be. I had to be escorted to my car. But I drove home relaxed, knowing I made the right call.