The 6.6kW referred to as the max power of the charger is for the DC output not the AC input.
The OBC has an efficiency rating at best around 90%. You need to input about 7.3kW to get the max output.
Here's my car charging from a 32A 220V EVSE.
The DC output power (not shown - we call it Energy Draw in our Torque codes) would be about 6.25kW.
That value is used to calculate the OBC efficiency.
The codes for using Torque Pro can be found by clicking the link in the website icon under my user name on the left.