Solid Infill Outline Speed

[SpoonUnit]

I've looked and fiddled with every setting the looks relevant, but I cannot figure out what is making the outline speed on the solid infill layers operate at a different speed to the outline speed for my other layers. Could someone suggest a place to look? The problem is that this is creating a different finish to the material, and I really just want the same exterior finish on all layers. Here's how the movement speed is being presented within S3D:

[CompoundCarl]

I'm guessing it's cooling. If you had 3 top solid layers for example, those top layers will take much longer to print than the sparse infill below them. For small objects, you have to provide enough time for cooling, so the print speed will slow down some for the sparse infill layers to make sure they don't print too quick.

This is most definitely a GOOD thing, but if for some reason you don't like that, you can disable it on the Cooling tab

[SpoonUnit]

Absolutely spot on. After disabling cooling, all layers are shown to be at the same speed. At least I can take this into account for calculations now I'm made (re)aware of this potential impact. I hadn't even considered this given the size of the layer, but this is what seems to happen when you use a crazy 1.2mm nozzle. Many thanks for your answer!