A LED is a forward bias device. The Drok regulator is working as a constant current led driver. In CC mode the voltage varies according to the applied current, you can see the Forward Current vs Forward Voltage curve in any datasheet. You will notice that a different voltage is applied for each current.
Learn what Voltage(electric potential difference) is, and you will find out how LED works.
About these LEDs under no circumstance are inexpensive, as you said 1212s are a big deal.
Your setup in not efficient at all. 87% at full load converting AC to DC and around 80-85% regulating the DC input and am not considering the fans(4w-5w each one or maybe more).
I can measure both 1212s and the pink one if you still are interested in what are you experimenting.
