Why does same image trace setting result in poorer outline, depending on file size?

Hello,

I'm relatively new to Illustrator and am wondering 1) the same setting for an image trace result in a wildly different result depending on file size, and 2) is there something I can do to force the outline in the larger file to result in the same trace?

Images below: settings I've used; overall image; detail with trace outline (cut from larger image); and the same detail when part of the larger file.

My desire is to have the finer detail trace outline over the full image.

Any ideas?

Thanks,

Paul

(using Ai CC 2018, on a Mac)