Depending on the timeline, it could be that they're not allowed to access Mythos because of something like non-US citizens on the team or the lack of some way for them to meet the constraint DOD has them under.

I strongly suspect if that was the case they would have just directly mentioned that Mythos couldn't be used because of that reason, it would be less confusing and less suspect messaging than saying it wasn't an "apples-to-apples comparsion".