Paint on a new airliner is usually applied in two stages: first, a coat of primer, and then a top coat  A new process requires no primer, but instead uses two layers of the same newly developed coating, with each layer of the new coating having the same thickness and weight as a traditional top coat
Using the new process instead of the old process increases the price of a new aircraft considerably
A layer of primer on an airliner weighs more than a layer of the new coating would by an amount large enough to make a difference to that airliner's load-bearing capacity.