If your normalize space function was working it would work for all scenarios.
I thought you were @RELM_NME[concat(txt_RelmNumber, " ") = @RELM_ID]
So for thee character nubers yu were adding two spacs to the entry.
For two spaces you would add three spaces.
You may add a message box to verify it is detecting AAA. Then at least you know that part is working.