We have an excellent battery wiki in this forum and I don’t think the numbers are wrong:
The E5CD should have up to 75.9 kWh usable capacity (more common is 75). The rest is hidden in a variable top buffer. Typically, 70 to 71 kWh can be extracted from 100 to 0%. I have never seen reports of 72 to 73 kWh. Do you have a source for that?