I add Pause at Height but that makes no difference in gcode, both files are compared the same. I see no M601, G04 or any of the codes I find online.
Looks like if I save the gcode NOT as Creality format, the pause command appears, now to see if it works:
…
;TIME_ELAPSED:9876.783520
;TYPE:CUSTOM
;added code by post processing
;script: PauseAtHeight.py
;current z: 10
;current height: 10.0
M83 ; switch to relative E values for any needed retraction
G1 F300 Z11 ; move up a millimeter to get out of the way
G1 F9000 X190 Y190
G1 F300 Z15 ; too close to bed–move to at least 15mm
M104 S0 ; standby temperature
M0 ; Do the actual pause
M109 S200 ; resume temperature
G1 F300 Z11
G1 F9000 X109.59 Y119.902
G1 F300 Z10 ; move back down to resume height
G1 F3600 ; restore extrusion feedrate
M82 ; switch back to absolute E values
…