[trux]

Yes, as Walrus wrote, the holes should reduce the transversal resistance of the fin - in the place near the footpocket, the blade moves water only perpendicularly to the swimming direction, hence you spend a lot of energy with no gain of forward propulsion.

I suspect your holes are too small to have an effect you could sense when kicking, and only increase the drag in the glide phase. The plain round holes will also likely create more turbulences than the opening as we can see in jet fins - those channel the water more efficiently and with less turbulences.