Lionel Smoke Fluid - Difference between these two?

Buy the newest batch of Lionel smoke fluid. The older Premium Smoke Fluid I bought January 2015 produced very little smoke. The new Premium Smoke Fluid I bought in October 2016 produces much more smoke from the same engines. The bottles that had the labels falling off were the poorer Premium Smoke Fluid. The new bottles have labels that stay on the bottle.

I've never seen any difference in any of the premium batches and yes, the bottles have changed a few time in just a few years of the premium fluid being available.

The newest one, shown in the second link, is their latest bottle that was just released in December of 2016. Probably the same formula as the previous Premium fluid. They also released a few scented varieties as well. The few that I've tried seem to work as well as the unscented.