Slitherine

Hi - I've had a few games now, but never seen a double + points of advantage for shooting. On the shooting POA table there's only two + advantages that I can see - Bows,slings & javs against unarmoured Mtd not in one rank and the Artillery POA against various targets.I'm missing something here . How does a double + occur for shooting?
Thanks in advance to every one who posts an answer

Petefloro wrote:Hi - I've had a few games now, but never seen a double + points of advantage for shooting. On the shooting POA table there's only two + advantages that I can see - Bows,slings & javs against unarmoured Mtd not in one rank and the Artillery POA against various targets.I'm missing something here . How does a double + occur for shooting?
Thanks in advance to every one who posts an answer

Elephants shot at enfilade by artillery;
Mounted in 3 ranks shot at enfilade by artillery.

They are the only two examples I could see.