Yes it is a huge difference. I'll weigh in. I believe LE's original observation and estimate was pretty accurate. I can't say what they based it on, perhaps it was a cursory guesstimate. In an effort to narrow down the measurements to a more exacting range, they called in a team of video experts to do an independent analysis.
When researching this exact subject, I learned this kind of forensic analysis is much more complex than meets the eye. Height estimation alone requires multiple techniques, at least three different kinds of math, extensive knowledge of perspective and how it relates to and links geometry and videography, and even knowledge of anatomy to some degree. Even if you have access to the scene, and some spiffy tech equipment, you must still know and apply all the above. Measurements - no matter how accurate - are simply not enough.
If you're going to reconstruct the scene with scale items or people of varying heights, you must reconstruction the scene identically. The same cameras and settings in the exact same location, the same items/placement, etc. Being off by a single degree at a distance of 20 feet can throw your measurement off by more than 4 inches.
I truly hope the crack LE team applied all of these techniques. I hope they have this level of knowledge of the subject. I assume they do, but have no way of knowing. Even considering all of this, it's possible there was a miscalculation here or there. I have checked, re-checked, re-re-checked my measurements, as have others. I'm very confident with my numbers and completely baffled at LE's numbers. As I've said before, I hope someday I will learn how they arrived at their numbers.