Hmmm... "looks" similar, but it's not... there are a few key differences - one you've already pointed out. Another is where the weight is centered... and how it is distributed.
It should be noted that how he (Yao Chengguang) is using stance there goes beyond the stance. That is one stance among many, and those stances are merely bridges to being without any fixed stance at all, such that regardless of where your body or balance is placed, force is well coordinated. The coordination is primary, the positioning is not. I would not read too much into the external appearance of it, since that's not really the goal of it at all.