Welcome to the site. I've been involved in some lively casting mechanics/physics discussions at Sexyloops in the past and have learned that even slow motion video does not always show what happens. On distance casts, Paul hauls well into counterflex and "appears" to not release the line until the rod has reach near maiximum counterflex.
During this discussion another discussion was goiing on called "Cast and Release", where the line is released "early" very slightly before or exactly "at" the rod straight position, and there is no "stop" on the presentation cast.
In an effort to pinpoint the exact and actual release point, and to see what the effect release timing has on loop shape, loop shape morph, and distance, I made up a comfortable momentary switch that could be held between two fingers in the hand with the line between the large button switch and the thumb which activated red LED's.
When the line is released, the light goes ON (or OFF depending on the switch
connection) The switch and leds are ridiculously fast, reacting within just a few miliseconds. The switch has a total throw of about 1/16th inch.
I sent it to Lasse Karlsson who made a good video varying the release timing, but Paul has not yet cast while hooked up to it. Lasse also taped a marker to the line, and discovered that line begins shooting immediately with the earlier release(and haul) but is delayed significantly with the later release and haul. The led is on a stick in the foreground.
I am still hoping that one day while Paul is still young, strong and energetic, he will get the chance to spend some time on it (camera rolling) casting to a tape and going for max distance enough times to get a good averaging.
It is that light which made me eat my words about George Roberts' article on shooting line into the backcast even WHILE beginning the forward translational part of the forward cast. I had tried that George Roberts" method after reading about it, and posted on Sexyloops that I thought it was an editinig error and that it was not possible to cast that way.
After taking a video of myself to see how the light worked, I discovered I had been using that (his) technique for at least 35 years without even realizing it. Furthermore, when I consciously tried to do it from his description (of exactly how I cast) I could not cast at all.
It is that technique which causes me to disagree with Paul about the concept of "pre-load" (which is not that good a desciptive word) for what is meant by it - namely, sudden rod loading.
Yeah, I know what I'm doing - - UH HUH! DUH!!!.
PS: The only good thing about "Foot-in-Mouth" disease if that you usually remember each occurance.!