sorry I forgot to mention that about AGCH load with BLKS=1 and PREEMPT activated. It was increased to around 30%.
Immediate_assign_command discarded due to congestion it remains in 0%.
What you think to not go directly to blks=1, first blks=2 see what happens. If it’s still OK then to go to blks=1.
Thank you very much for your proffesional suggestions,