Members of the choir do not make those choices. The conductor does. The singers are the instrument in that case. Like a pipe in an organ. Their job is to blend

Members of the choir do not make those choices. The conductor does. The singers are the instrument in that case. Like a pipe in an organ. Their job is to blend and produce the sounds according to the interpretation of the conductor. Source: am a choir member. You will be fired if you interpret the music against the conductor's desires.