To me, your leg extension in your previous video actually looks fine to me. A LOT of people have their saddle too high in an effort to maximise leg extension when it really isn't necessary. The only thing that is going to limit your sustained power output is your cardio engine, not your ultimate leg power. It doesn't look like you are cramped at the top of the stroke either, which is what happens when you really do go too low on the saddle. Maybe you could go a little higher without running out of your "functional" leg extension range, but you won''t gain much, if anything, from it. But if increased saddle set-back feels good to you, then go with it.
One thing I did notice from your video is that you have your arms locked out and shoulders tensed up. Try to relax your shoulders and bend at the elbows a little. It helps to rotate your pelvis forward slightly and use your core to support your body rather than pushing down on your arms. Actually moving the saddle back should help a little with this.