3-4s per lap...? So overall 2-3 more laps in 5 minutes...? Sorry, but I don't buy it.

Not that your times didn't maybe improve dramatically, I'll give you that. But that it was just because you added another 5-10A on charging is not credible. After all, that's a world of difference you're claiming here. Sorry, but it really is much more likely that you actually simply drove differently (=much better) for some reason - and if you had had the same good run with a battery charged at 2C, it would not have been a 22s per lap average either, but up there with the times you got.

Do you really believe that doing this 40A charge/discharge method will cut down lap times by ~25%??? (You claim to be close to 20% already, and you seem to expect another major jump from your 18s times) IMHO that's just wishful thinking - it's simply not how it works. Hell, stepping up the motor one category (e.g. 17.5T to 13.5T) would most likely not give near as much of an advantage per lap as you claim, let alone just charging the battery a little differently... It may give you a few(!) tenths of a second, but certainly not several seconds (especially at such a short track). It's still physics, not magic.