Complex sentence: A variant of the Group II with upgrades to the mission computer and CIC workstations is referred to as the MCU/ACIS, these were produced in small numbers due to production of the Hawkeye 2000 soon after its introduction.
Split into simpler sentences: A variant of the Group II with upgrades to the mission computer and CIC workstations is referred to as the MCU/ACIS. However these were produced in small numbers due to the Hawkeye 2000 being produced soon after its introduction.