Exactly Mike, I hadn't even looked at that closely... WAY too big. Hell, two Wookiee's are on the "drive wheel" portion in the center planting the bomb, and they practically take up 3/4 of the wheel's overall size, and Wookiee's are big, but not that big... That chart's all over the place and pretty off in general. The tank droid's pretty small overall, so yeah, that's just not a good gauge.
I think there's a couple types of juggernaughts listed (not sure why, probably covering up the "Juggernaught/Turbo Tank" screw-up in naming), but regardless, there's other vehicles there that just aren't right regardless of what texts say. Film examination shows AT-AT's were intended to be a LOT bigger, and that even carried over between films so it was pretty intentional.
Snail/Tank Droid must have a big brother if that thing is "accurate", haha.