The only argument for 1PPI that I could see is the proximity to Exit 6. I personally think that because it mainly serves two roads not served by Exit 6, nor does it overlap at all/share ramps with Exit 6, it is a separate interchange.
This may be a bit of an exaggeration, but IMO considering CCP Exit 6/7 to be one interchange seems the same as calling Exit 4/5 on the Saw Mill River Parkway one interchange.