I have created a report for another Single Bullet Theory. I figured one SBT wasn't enough. 
You can find the report at this link:
https://sites.google.com/view/theothersbt/home
Please review this report if you are interested and let me know what you think. Thanks!
You have put a good effort into your paper, Charles. While your theory that a wildly missed shot is better explained by accidental firing, the suggestion that Oswald would have been so careless as to fire accidentally seems just as highly improbable as an aimed shot that missed the car.
I do have a few questions, though.
1. You seem to equate velocity with energy as in: "The impact of the first ricochet (off of Elm Street) would have reduced the velocity considerably. We have to assume some values that seem reasonable. If we assume it lost about 31% of its velocity/energy,". Energy varies as the square of velocity so if the bullet loses 31% of its speed (retaining 69%) it ends up with .69^2=48% of its original energy, not 69%.
2. You say "the end point of the calculated trajectory as the bullet mark on the manhole cover, the graph shows an elevation drop of about 13.7-feet in about 83.3-yards (similar to what actually exists in Dealey Plaza). One of the main points that needs to be understood about the graphs is that the trajectories are essentially horizontal (level) for the first half of the distance, and slowly curve downward over the course of the second half.".
A fragment is still a projectile and follows the laws of physics. Neglecting air forces, any object drops at g=9.8 m/s^2 (32 f/s^2). So if it starts with zero vertical velocity, the distance, h, that it falls is proportional to time^2: h=gt^2/2. So t=√2h/√g. And since horizontal speed does not decrease much, time is proportional to distance travelled (t=d/v).
If the bullet hit the pavement and where you suggest and a fragment deflected at a 3 degree angle above the road surface so it started perfectly horizontal, in order to drop 13.7 feet (to the level of the manhole cover 83.3 yards or 250 feet) away, 2h/g=2x13.7/32=.856. So t=√.856=.925 seconds. So it would take .925 seconds to travel 250 feet. This means the fragment was travelling at an average speed of 250/.925 = 270 fps. So that fragment has lost 1-270/2165 = 87.5% of its initial speed, and 98% of its initial energy. If the bullet lost 98% of its energy in hitting the asphalt - ie. 600 [edit: this is wrong. 2000 fps is 600 m/s which works works out to 1800 J.] joules of energy would be deposited in a tiny area of the asphalt - there would have to be a significant movement of asphalt around that area.