I believe so, i think that's the battery back up time.
I did mine at the weekend, disconnected the battery, touched the leads together for good measure (in case there's any stray capacitance anywhere) and left it for 5 hours. And that worked.
I only left it so long cos i went back to sleep, had a migraine. Woulda left it no longer than an hour otherwise.
Reset the ECU this evening and have driven about 20 miles since. The car is struggling to tick over now
I'm assuming it's gonna have to learn all the settings for different engine temperatures, air temperatures, throttle loads and mixtures of all 3 ?????