In searching for a R/T: Mia / Fll - LAS (Mar 5 and Mar 10)... i get different first fares depending on the "search criteria" for the outbound city.

For instance:
3/5/19 - MIA/FLL - LAS: Flight AA 1368...... prices at: $1,446.00

BUT..... if I change the "search criteria" for the outbound city to ONLY Mia (.....to LAS)... that same flight prices out at: $1,534.00

Any thought son why this is????

AND..... in the search .....R/T: Mia / Fll - LAS (Mar 5 and Mar 10).... it does not pull up all the possible connecting flights.

For instance:
3/5/19 - MIA - LAS: It DOES show: MIA - ORD AA 335 and ORD - LAS AA 168

BUT..... if I change the "search criteria" for the outbound city to MIA / FLL (.....to LAS)... that flight option is not shown.

Another deficiency in the AA site.... and another reason that I am constantly forced to use 3rd party sites (ITA) to find and book flights.