Let me start with an analogy: You want to find which car travels the fastest, you set them to race 1 kilometer, you arrive at the finish line 3 minutes after both cars have finished.
Recoil plots need to show time in a way in which we can distiguish which gun recoils less or more. The m416 and the m16a3 have nearly identical recoil plots but the m416, being the lower recoil gun appears to be on par with the latter gun.
Aside from that, M416 doesn't really have less recoil. It has a lower first shot multiplier, and the illusion of lower recoil since the rate of fire is lower. Otherwise, it has the same horizontal, and slightly higher vertical recoil than the M16(A3). They still wind up being about the same, it just depends on your tastes.