Seltzer vs vodka, help me with some calcs

A) 1 shot of vodka is 30ml, 40% alcohol (12ml) and has 95 calories

b) 1 can of seltzer has 330ml, 4% alcohol (13ml) and 77 calories

C) Vodka is widely considered the lowest calorie alcohol.

So seltzer has more alcohol than 1 shot of vodka, but less calories? How is this possible?