It's been a while since my last On-Call CAS. But as far as I remember.... you don't get targeting
data any better than that.
Anyway the FAC's raw vector is only to have you reach the generic target site. Then it is your
call to deal with whoever you find (so long you don't harass allied troops). It's a Discretional S&D
provided that you don't stray too far from the appointed location.
To this end you may want to take advantage of the 'Mark' feature (look it up on the ICP/DED) to
ideally 'pin' down on your HSD the location pointed to by the FAC. You can plant up to 7 marks,
IIRC, and they work like any regular steerpoint (so you can see them on the HUD and even alter
their GPS coords, again IIRC). Practice with it in a training mission. It's very easy to use.