Error with residue selectors not counting indices correctly.

I have a 4 chain, 96 residues long PDB file. all four chains are identical, so I set up my rosettascript with the following indices to select each chain to mutate them.

<Index name="chain1" resnums="1-24"/>

<Index name="chain2" resnums="24-48"/>

<Index name="chain3" resnums="48-72"/>

<Index name="chain4" resnums="72-96"/>

However I get the follwoing error message when running this script: 

ERROR: Provided invalid residue selectors. Each linked residue selector must define the same number of residues. Selectors of type Index and Index were found to specify 24 and 25 residue(s), respecitvely.

The pdb has already been renumbered and I have tried using other residue indices but the same error appears. Thoughts?