That's right
The GVOD has two stipulations;
1) you cannot be in OD and simultaneously back up,and
2) you cannot downshift it while it is under power.
With a manual trans selecting a split gear requires you to declutch, then shift. I have found that you can do this simultaneously; if you hesitate just a few milliseconds while it engages ALL THE WAY. The GVOD uses the driveshaft to drive it's internal pump to make the pressure, so the slower you drive and the lower number your gear, the longer it takes to shift.
So with 3.55s,I normally do not split first and second unless at WOT and winding up past 5000rpm. With anything over 4.10s it was not a problem.
I have no problem downshifting into a split gear,when doing it properly.
With an automatic,You cannot declutch, so it would require a bit of learning to get it right. The standard ratios work pretty nice. 2.45-1.91-1.45-1.13-1.00-.78, with splits of .78-.76-.78-.88-.78into OD. GV ratios in red.the split from 2od to 3od is .69;pretty nice.
If you gear to trap in 1.13 ratio you will post a good run. For a 106mph car this might be 4.10s and the starter would thus be 10.0, and the cruiser would be 3.20s, making 65=2580 at zero-slip with 27s; pretty sweet deal. And the 4.10s will slam the GV into gear tire-chirping-hard when used as a splitter.
If you just want to use it as an overdrive, then their ECU will take care of things.