As Bmadd34 said, PT is based in Bangalore India. I'd be surprised if the PT engineers didn't have a lunch or two with RE engineers, an opportunity not easily afforded to PC V engineers.
Like the PC V, the PT device is a "piggyback" to the Keihn ECU. C5 installation requires connection to the TPS, ignition coil, fuel injector, and "Ckp". Next to last installation step is start the motorcycle with "Stock Coupler" aka "stand by unit" plugged into PT device connection. If it starts, replace with PT device. If not, follow their troubleshooting flowchart.
Of course I wondered about their use of the HEGO sensor. From their
http://powertronic.racedynamics.com/faq/ FAQ:
"Does the PowerTRONIC use the lambda sensor?
"The PowerTRONIC will allows overall ignition control in all operating points, and fuel control in the open-loop region of the original vehicle operating characteristics. The original lambda remains, and will help run the bike at optimal AFRs in the cruising region. You would see a much better throttle response and dynamics engine characteristics, along with safer air-fuel ratios at non-cruising conditions."
My reading of that answer is the PT's open-loop AFR map engages when the throttle position is changed or is WOT and the Keihn's closed-loop AFR map engages with steady-state partially-open throttle positions. The PT device is apparently aware of the Keign HEGO as implied by the map names at
http://racedynamics.com/downloads/maps/Royal%20Enfield/.
If I'm correct the PT operation is more subtle than the PC V whose operation apparently bypasses the Keihn ECU with open-loop AFR at all throttle openings and position changes. The PC V includes a HEGO simulator so the Keihn doesn't light the MIL. If you want closed-loop AFR then you add the Autotune AT-200.
I'm looking forward to Bmadd34's review. While electrically less sophisticated than the PC V, functionally the PT seems more sophisticated.
One amusing installation note is this:
"We have often observed that the original relays provided are corroded, worn or of an inferior
quality. This can cause jerks at certain rpms. You might not observe these symptoms
without PowerTRONIC as the stock ECU works only on the preset map and does not look at
signals or injector supply."
"When the injector supply is faulty and fluctuates, PowerTRONIC would be unable to optimise
fuelling and this leads to jerks/stalling while in motion. Replacing the faulty relays has been
shown to eliminate this issue."
On the C5, the highlighted relays are the two to the left of the flasher relay.