This might go in the "duh" category but I just realized it a few days ago. It was so subtle and I never RTFM so I didn't notice it.
The "bubble" power meter on top of the dash shows power and regen using the white dots. That's pretty obvious. But it also shows "available" power and regen. When the pack is fully charged, regen is not available. You will notice the inner circles of the bubbles in the regen area are not illuminated. As the pack discharges and regen becomes available, the circles will illuminate indicating that regen level is available, and the white dot will go there if prompted.
The same thing occurs on the power side when you start to approach turtle mode. In turtle mode you'll only have 3 or 4 circles, which quickly dwindle to one.
Ford F450 Crew Cab Hybrid Conversion