thank you for your kind advice.
as you mentioned that it ensures the conflict reading of sys A pressure drive on the gauge, I am so all with you.
However, what I see is that the sys B ENGINE pump (with a sensor) is the only system which could only drive hyd shutoff valve to PTU OPEN, not the ELEC pump. Accordingly, that is the reason I am so doubt about Turning sys B "ELEC" pump ON before the sys A "ELEC" pump on. with this issue, it might not have something to do with the PTU.

Please kindly advise