I'm going to be optimistic and hope that this is a bug.
The only other thing I can figure is that
1) Other fuels are more efficient (Wasn't Deut supposed to be considered a high-grade fuel because of its price though?)
2) They nerfed it on purpose because it was working too well on ships with huge cargo holds, like transports and liners, who could stay invisible for very long periods of time. In which case I would say, then make a transport cloak that consumes fuel faster and is cheaper to make. Make the battleship shield consume at the original rate of 1 per second and make the max size ship it will fit on 2000 cargo space or whatever the largest BS is.