This video summarizes the issues I’m having. But in a nutshell, I’m trying to scale up an edge loop along the grid, and then go back later and tweak it while keeping it snapping to the grid the second time.
The video demonstrates the problem.
No. The absolute grid snapping is for translating (grabbing, moving) as the tooltip says. The increment for scaling happens in 0.1 blender unit steps, which happens to follow grid lines at first but not when scaling afterwards. Radius of 1 scaled 1.1x, 1.2x, 1.3x all follow the grid lines, but then scaling 1.3 radius by 1.1x = 1.43.
If scaling it by eye is not enough for some reason
(scaling by eye even roughly by zooming in a bit is more precise than the inherit precision of a mesh circle that consist of 32 edges)
then would need a snapping target to use vertex snapping while scaling, or
use scaling factor of wanted/current diameter or wanted/current radius. Can input that on the operator panel afterwards or with python input (numpad_*). Above I entered 2/1.4 in the field (=1.42857142857) and the result is 4.
Avoid asking questions with a video. Most avoid watching them. It’s much easier to close the thread tab than sit through a video just to understand what you’re asking.
That question can be explained with one screenshot, then the post only needs an example .blend file for troubleshooting and as a starting point for answering. If you’re using a .blend file, then your support question is going to need one, and your time is much better spent preparing one than recording a video.