M221 flow change request missing

[Pridanc 2]

Folks, as I continue my new journey into the world of FDM printing, I recently upgraded to CURA 5.4  (from 5.3.1) and yesterday I wanted to test for the best settings on my printer. It was time to run the Flow Tower test and I chose the one that comes with CURA under the Extensions, Part for Calibration, Add a Flow Tower Test   as that would do a sweep of 115% down to 85%.

 

I sliced the Tower and ran it.  The tower printed fine but as it progressed I saw no change in flow (from the stock UI of the Ender 3 v2 machine.)  from the normal of 100% where it sat the entire print. Not what I was expecting to happen.

 

I thought I'd attempt to see why the flow never changed so I opened the gcode in Notepad++.  Not knowing what I was looking at, I first went to Marlin to learn what the Flow command was and learned it was M221.

 

Once I learned that, I went back and inserted M221 S** (S** being changed seven times to request the seven flow % changes.  So  M221 S115, then 110, 105, 100, 95, 90, 85 until each appropriate layer of the gcode had the necessary M221 S** request.  I then ran the tower and it printed perfectly changing flow as the tower printed. 

 

I know nothing about Marlin or gcode so I may be missing something here but isn't there supposed to be a request in the sliced gcode to request the Flow % change?  Understand, I am a 3 month user so am completely without knowledge. 

 

 I look forward to learning your thoughts after you've had a chance to consider this. This issue aside, thank you all for the supreme efforts to helps us all by supplying the CURA slicer. It is appreciated!

CURA Flow Tower Test 7.7.23.gcode