If I'm holding a Rod of Absorption, and an 11th level opponent casts Scorching Ray (getting three rays), and targets them all at me, how many spell levels get added to the rod? Is it two, since it's a single level two spell targeting me, or is it six, two for each ray?
Well consider the following:
"how many spells are being cast?"
It is 1 spell that produces 3 attacks. But at the end of the day, the rod absorbs 1 spell. So
2.