Top Layer Field Quality

[sdb999]

Ender-3 S1
Slicer: Cura
Material: ABS
Tip: .4
Temp: 240
Bed: 100
Layer Thickness: .2
Speed: 50
Cooling: off

Have been struggling to remove a specific roughness in the final top layer. Just inside the perimeter wall, which is very smooth, I have clumping/roughness that fades towards the center of the print. I've been adjusting top layer thickness (which helped) top skin, extruder temp, top layer pattern and a few other settings specific to the top layer. If I didn't know better I'd say it's related to the decel/accel of the extruder as it changes direction but not sure. Looking for another body of knowledge....mine has run dry. I'll attach pictures that should show the issue pretty well. Especially samples 1 and 2. These are about the size of a standard domino.
Thanks, S.


Dominos.jpg Dominos 1,2.jpg