The difference is due to the design of the Circuit Breakers. The Compact NS>630 manual basic frame (bloc cut) is different from NS electrical basic frame (bloc cut).

Ics depends on breaker type. Electrically operated Compact NS>630 is developed from Masterpact NT breaker because there is no option for adapting the motor mechanism on Compact NS>630.

The breaking performances of NT are less than Compact NS, hence it cannot be declared that the Ics values of electrically operated Compact NS>630 is same as manually operated Compact NS>630.

This is the reason why the service breaking capacity (Ics) values of manually operated and electrically operated Compact NS>630 MCCB are different.