Yeah, he's notching, or just attempting to. Most notching I've seen is top down from straight vertical, this is interesting because he uses arrows to get him true 45 degree, which isn't that hard without arrows. The only shots he notches correctly on a consistent basis are 45 degree FP nade/petrol and full power blue wind. He seemed completely unable to notch red wind, and inconsistent with middle blue winds. He hits a few full power shots, but they seem more based on distance, he moves his worm to the same spot over and over again to get his distance right instead of adjusting with aim. It is extremely crude notching that doesn't really work well for real situations, I could mop this guy up in BnG or hyst. Fort is ideal for this sort of crappy notching, doesn't work anywhere else, honestly.
Many have notched better than this, he's not even that good at it.