Yeah. Each square unit adds to the cost of LN2, but each cubic unit adds to storage capacity. With spheres and cubes alike, the volume goes up on a cube law where the area goes up on a square law.
A cubic meter would hold around 100 heads or 10 bodies. A thousand cubic meters in a cubic shape is just 10x10x10 meters, with 600 square meters. So if the energy cost is $100/month per square meter, 100,000 neuro people could be stored in something costing $60,000/month to run. 60 cents, in other words.
And like you say a dome with that volume would have less than that in square meters... 40-50 cents maybe.
And domes are structurally better all around, of course. Less hurricane or earthquake risk by far.