PID Error Calculation

Recently I've been tuning my system by first setting the PID coefficients to 0 and setting the FF* block to make the following error (as seen in halscope) as small as possible.  After that I tune the PID to compensate for the vagaries of the system.  When I tune this way I think there should be a one stage delay between the command input and the command/feedback adder.  The idea being that if the FF* tuning was perfect there would be no following error resulting in a zero out of the PID.  Without the delay the PID would always see an error due to acceleration.

Has anyone considered adding this delay stage?
 

I believe that is done by setting the error-previous-target parameter true

OK, I see that in the code. I was looking at the diagrams.

It also helps to look at the PID-error instead of or in addition to the joint or axis f-error when tuning.