I'm looking to add a G4 code after spindle start (G4 P3) but cannot determine where this is defined within SolidCAM.

I have added....

@delay
gcode = 4
{nb 'G'gcode, ' P'delay_period:integer_def_f}
endp

..to the post processor but but cannot establish where/how this is called.
In the Machine ID Editor it shows a dwell under the Spindle device which is set to 'Value' but nothing comes of it

Any help much appreciated