I have a Felder KF500 that I'm setting up to make a relatively narrow groove (11/32) using a Forrest Dado stack. I've used the stack before for larger dados and no issues. The manual for the saw states that for grooving less than 10mm (11/32" is less than 10mm) that I'm supposed to use an extra spacer on the arbor side of the stack. However, when I do that it pushes the outside blade of the dado stack EXTREMELY close to the sliding table, like less than a 1/64 and doesn't seem right to me. Have any other folks with a Felder or Hammer saw encountered this? I'm wondering if the spacer is specific to the special Felder/Hammer grooving cutter and doesn't apply to a more traditional dado stack like I have?

Thanks,
Tom