This is typical response from multiple CSR. It’s quite obvious UA has cut down or even eliminated spending money on training their employees. Very sad.

I guess my theory holds correct. Call 3 UA reps and you will get 3 different answers

On the other hand, Lets hope you get upgraded to a 3-cabin as the seats are always better in Biz than F on a 2cabin. Give me the flight number and date and I can do a experflyer to see how the seatmap shows.