Per the CASA Part 66 MOS, 66.A.23 Requalification Requirements.  For an engineer who has not been able to achieve the 6 in 24 requirements,

This training is designed to satisfy 66.A.23 (b) 2. Where the engineer can undergo training and receive a report from an MTO authorised for type training, to “revalidate” their licence and bypass the 100 days retraining.