Mike,

I think the confusion lies in the difference between stride length and beaten lengths measurements. The measurement used for beaten lengths is from the horses nose to his butt (average 8 ft.) and where the hooves are is not part of it. This is not the same as stride length which measures how far a hoof goes from where it leaves the ground in one stride sequence to where it lands on the following stride. The 2 are different measurements and the 8-foot measurement is the one used in beaten lengths.
I made a slight error when I said that the 8-foot length does niot change since it is slightly longer during the extension part of the stride than during flexion. However, since a running horse spends the same amount of time in flexion and extension the 8-foot average holds.
It is entirely possible that the TG measures of ground loss and Trakus can vary for a particular race and this would give a different ground loss adjustment but it has nothing to do with stride length. The difference would be entirely due to how much ground loss was measured by each.

Bob