Yeah, but the 3 Speed HST on the 1526 has the ranges to still get enough to the ground. I would not fear the 1526 HST, except for field work the shuttle would put more HP to ground.
The 8 x 8 semi synchro mechanical shuttle seems to be a good transmission, I like it far better than a straight 3x2 grind them or find them straight gear I moved up from. With the shuttle I just putter along at <1500 RPM, nice and quiet, save fuel, no hydro whine. Kubota got it right when they offered the 3 speed HST on the B series.
About only place I would want an HST pedal is close in loader work, backing up to implements, Loading shiny new Pickups, etc. for the easy fine control. Still I like the 8 forward and reverse speeds the shuttle offers.
My 2 lawn tractors are HST.