Yep. The transmissions aren't even close to being the same.
Cahaba Valley Farm said: Why? Because of the number of ranges?
Yes, but it isn't Ranges. Both have 3 ranges. The difference is in the ease of shifting ratios within a range. One can do that & the other can't. If you like HST, you'll love HST+.
Any HST is nice for doing chores & projects, but for some reason the shifting between HST Ranges L/M/H is real awkward. For range shifting not to grind and shudder you still have to completely stop the tractor and then work a lever that is too short for what it needs to do. Range shifting reminds me of an old style "crash box" manual transmission without any syncros or clutch.
The H/L switch on the steering wheel of a HST Plus type transmission is like a two speed axle in a truck. It splits each range into twice as many ratios and that allows the ranges themselves to be farther apart. So each range covers a wider span...which farther reduces the need to stop and wrestle the range shifter.
Bottom line is that HST Plus transmissions are no better than the others at range shifting and they still have 3 ranges. The advantage is that having a fingertip high/low option in every range takes away most of the need for shifting ranges in the first place.
As a bonus, the HST Plus operator is are more likely to be in a favorable ratio, and that allows him to push farther down on the HST pedal so that more HST power can be used without so much HST whine. And it works in reverse, too.
Cahaba, that's a bit long-winded & I apologize. But it's what I meant when I said, "the HST and HST Plus transmissions aren't even close to being the same."