It's an option because it's a 709 ride - like
@USMCmech said, the ASI has a lot of latitude on this. And yeah, this has to suck for them, too.
I also find this one kind of interesting, because they've targeted IR/CFII stuff. Typically in a DPE-checkride-recall situation, the applicant is absolved from the 709 ride if they've passed a more advanced check ride after the one in question. So, theoretically, if any of these applicants have gone on and passed an ATP ride, for example, they'll probably be exempt.
What I'm curious about is if any of them passed an MEI or CMEL ride, since a single-engine approach is on both check ride criteria, if there was a precision approach, (or whatever IR criteria is in question) would that satisfy the FSDO/ASI?