I'm on a standard electricity tariff but have seen exactly the same behaviour. Charges at 32A when started normally but when scheduled it will sometimes run at 16A, evident in the morning by being partially charged. Given I'm on a fixed rate tariff there really isn't any point me scheduling anyway, I'm doing it purely to ease stress on the battery when doing a long drive the following day - i.e. keeping it at 100% for as little time as possible. In many respects, it would be better if I just charged at 16A for longer anyway, that's further helping the battery.
I'd like to see charge scheduling and charge rate built into the app, my old BMW 3series PHEV could do that years ago, but that is about the extent of what it did that was better. Oh, and the auto wipers....