Okay. I have limited time available, so a single easy to understand post would be appreciated.
Basically the thing is this.
Usage of speed statements within a story for a calc.
For example: Character A has a stated speed of X m/s that is not contradicted by more slower showings and is shown to be consistent (For this specific point) or has achieved this speed via some reasonable explanation like a power-up etc. Now, Character A fights against B, and Character A is explicitly stated to be operating at full power, and attacks B, but B dodges at the last minute.
Basically this scenario (Or a scenario where the speed statement is shown right as Character A attacks B and B dodges at that moment in the same scenario where the speed is blurted out by the story itself) would allow the usage of that speed value in our Projectile Dodging Feats Formula, provided the "Distance Between Character A and B at the time of B dodging" and the "Distance dodged by B" are viably calculable.
Basically there are conditions that must be fulfilled to allow this to work out:
1. The character attacking (Character A) MUST BE EXPLICITLY STATED to not be holding back and to be going all out and using their full power (and speed if that's what the others prefer)
2. The stated speed must prove to at least be consistent with the other speed showings in the story, or if it is much higher than the regular showings, the stated speed must have some reasonable explanation or justification within the story as to how the character attacking got that fast.
3. The Character dodging (Character B) would have to be directly reacting/dodging/parrying the attacks of the Character that had the said speed stated (Character A), they cannot qualify if they dodge an attack from someone else (Character C) that had once fought against the Character with said speed, so as to avoid further dilution of the feat.
4. (Optional) It is preferable if the dodging feat happens in the exact same scenario as where the speed statement is found for more accuracy and reliability to ensure that Character A truly was at that speed. If not, the other above conditions need to be met.
One example I can make of such a feat is this:
Character A plays a tennis match with Character B. Character A hits the ball so hard that it causes a sonic boom and a shockwave Character B only realizes at the last moment the true ferocity of that ball, and the story and Character B then both explicitly state that the ball has broken the sound barrier (343 m/s minimum). The distance between Character B and the tennis ball is reliably calculated to be 0.4 m, and Character B then swings hard into the ball at a 90 degree (1.5708 rad) arc with their arm. Arm length being 44% of body height and the character being 1.7018 m tall, thus having an arm length of roughly 0.75 m. Distance moved is thus 0.75 * 1.5708= 1.1781 m
Projectile Dodging Formula: (Distance Moved by Character * Velocity of Projectile) / Distance between Projectile and Character when the Character starts moving
Speed: (1.1781 * 343) / 0.4= 1010.22075 m/s (Supersonic+).
This is just an example. But it is no different than how we calculate bullet-dodging feats or feats involving dodging other projectile types. The only difference here is that instead of the real-life established velocities of various guns (Or even velocities of arrows for arrow-dodging), the story itself gives us the velocity of the projectile that the character is dodging.