Yes, the setup steps 7 and 8 are necessary in all cases.
Also, does the compressor need to be engaged at this step?
Yes it does.
With it on, the highest reading I’ve been able to get is 1.550VAC.
You need to check if the issue is in the DOA or in the side chain.
Check you get no DC volts at the output of the DOA on L1 top pin. Any DC above a few millivolts here shows that there is an issue with your DOA.
If you can check the DOA in another device it is a good thing.
With the jumper JMP1 on 2-3, what is the DC voltage on TP6 (against 0V) at the 2 extreme settings of P6: should be between -4.5 and -1.2VDC