Very poor upper surface on only one model, others are great

[Free2fish]

Hello, I’m a relative newbie to this hobby and am near the point of hair pulling. I’ve purchased a stirling engine kit that supplies several items while allowing the printing of most of the frame parts. The upper layers of the flat objects are horrible while those of ALL my other prints are perfect or as expected. Technical support of the company says the problem is with my printer, a Creality Ender 3 S1. I’ve been using the Creality slicer, a subset of the Cura slicer.Does anyone have any ideas how this could happen with only one model? I tried adding photos but was unable to get them below 20K. Oh, I see one of the photos showed up,I’ll try the bad one too.Thanks, Harry