Solo Duties Difficulty Select
the difficulity only appear after you fail them once, so it's only there if you failed and lost time regardless (unless you fail the 1st few seconds in and go for very easy, it really makes a difference)
That is simply untrue. You are presented with a difficulty selection upon beginning any solo duty.
As shown here, from my own (failure-less) run: 
Runs recentes
Nível: Ala Mhigo
Nível: The Void Ark
Nível: The Crown of the Immaculate
Nível: Alexander - The Burden of the Father
Nível: Sohr Khai
