In handlerordering.csv you can change order of handlers. But it doesn't work with ic2.neiIntegration.core.recipehandler.* handlers. I've tried changing ordering number (priority) to both -1 and 2 (cause everything else 0 by default), but they're still at the same place. Changing the order of other handlers (e.g. gt.*) works as expected.

I just tested this with with NEI-2.3.50 in GTNH and cannot reproduce this.

Specifically, ic2.neiIntegration.core.recipehandler.ScrapboxRecipeHandler and ic2.neiIntegration.core.recipehandler.SolidCannerRecipeHandler seemed to move around just as expected (tried values -1 and 1000).

Sorry, I didn't notice that the version was NEI-2.3.29. In new versions it works as expected.