German 88mm AT gun usage in game

[cjsiam]

OK, so working with some fall of france counters I finally took time to look at the 88mm LW AA gun....

it is a 12-15 8-9 ... Love the AT
But the 12-15 is Indirect fire....for this AA gun....

Is this telling me that I can fire the 88mm AA gun INDIRECT at up to 15 hexes?

REEEEAAAAALLLLYYYYYYY?????

Are we Flaking the ground at 3Km with Indirect, or what?
I saw no special rules about use of this AA unit....it's Combat factors are white bordered---Indirect....range of 15....

Does this strike anyone as ...well.... not viable?  AA?