It's all about what the pump really does in the circuit its placed in, flow numbers from the book will be a open test with no restrictions.

Some might not like this link because it's not a "MB" but it is very useful info showing REAL world pump figures. Intercooler pump flow testing results

Wish the person who installed the CM30 I just took out, didn't cut of the vehicle side connector if the OE pump does have a pigtail connector.