I really do think the car lacks a kw rate of charge display. Had the same problem in the UK. Charger should offer 7kw, car can only take 6.6kw but no indication of what was being received. Before leaving checked % against time to get to 90%, did some calcs in my head and realised it was only giving 2.3kw. The charger may indicate 7kw but that does not mean it is actually supplying it. Moved to the one a few slots away and it delivered the full amount.
Mazda give us a kw rate of charge indication please!