Oh zach, silly boy. Here's the deal. The accepted and "official" conversion from hand timed to fully automated (FAT)(ACCUTRAC) in the 100 and 200 meter runs is +.24. That's not up for debate.
#1 that's for a FULLY AUTOMATED (FAT)(accutrac) vs. hand timed. In practice it's generally accepted to be between .15 and .24.
#2. Again, SAPRQ is NOT fully automated. It combines a human starter and a laser finish.
#3. Ask yourself, what is the distance between runner A and runner B that would correlate to say .2 in a hundred meter dash? How bout the 200 meter dash. A 40 yard dash? Are these distances the same? Hardly. The farther the distance traveled, the greater the difference between the runners .2 would represent. For example in the 100, a .1 represents 1 yard between runners A and B. Agree? Does .1 represent a full yard between runner A and runner B? Nope. More like less than half a step. But for s**** and giggles let's just say it's half a step. Are you getting the picture.
I'll summarize. The "SPARQ" timing method used to time 40's is a combination of human and laser timing. So right there, the accepted .24 difference used to convert a hand timed 100 meter time to an accutrac (FULLY automated )time. Does not apply. In keeping with the accepted .24 difference reference, it pertains to 100 or 200 meter runs. Not the considerably shorter (almost 1/3 of 100 meters, 110 yards) distance of 40 yards.
If it helps, I spent time with 3 different pro teams in 4 years. Because of my approach to training and preparing for my career @ tOSU and a pro. I became a consultant to many others to help them improve themselves as runners. I later became a certified trainer and also trained and consulted athletes in pro basketball, baseball and football. I ran track myself and so does my son. Trust me I'm well versed in timing methods and the differences I spoke about above.
In closing, down on your knees mother****** and bow to the master. That's right, the master. Don't you ever question me again. EVER!!! Got it!
Just kidding buddy. I'd guess what I just said still won't alter your way of thinking. For the record though. You're off in you conversion calculations.