Honestly, I think all the different dilutions are "real stuff." It's just a matter of how many drops you need to get the dose you're aiming for.
They said the included dropper was metric, which according to their chart yields 3.15 mg iodine/iodide. That matches with thinking that the solution is 2-1/2%, since the usual 5% Lugol's drop is 6.25 mg iodine/iodide. Using their dropper, you'd have to double up what you've been doing. Using a different dropper for which you don't know the size drop it delivers, I wouldn't know what to do except guesstimate according to taste. Sometimes there's as much art as science in iodine therapy :)