KarinsDad said:
By the example in the Empower Spell feat itself:
"roll 1D4+1 and multiply the result by 1-1/2 for each missile"
basically states:
"roll 1D4+1 and multiply the result by 1-1/2" pause "for each missile"
(1D4+1)*1.5 + (1D4+1)*1.5 + ... + (1D4+1)*1.5
In this sentence, the phrase "the result" must be referring to a single 1D4 + 1 (basic English sentence structure).
Granted, and pretty patently obvious. I don't think you'll get any arguments from anyone here.
I still don't see the logic that then applies this same methodology to, say, a fireball spell, in that each missile is discreet whereas there's only one single ball of fire.
The alternative reading, by the way, would properly be (assuming you've quoted correctly):
Roll 1d4+1 *pause* and multiply by 1.5 for each missile.
This would mean a normal, un-metamagicked version of MM cast at CL 5 (three missiles) would produce three missiles, doing, on average (1d4+1) * 3, or 3.5 * 3, = 10.5 damage.
However, when Empowered, the spell would do (1d4+1)*1.5*1.5*1.5 (as in, multiplying by 1.5 for each missile). This would result in average damage of 3.5 * 1.5 * 1.5 * 1.5, = ~11.8.
That's pretty obviously a wonky reading of the text, however.
The correct answer is (1d4+1)*1.5 + (1d4+1)*1.5 + (1d4+1)*1.5, = 15.75.