It is obvious non-rated pilots are subjected to a higher failure rate than type-rated pilots in KAL. Of course a non-rated pilot will take some time to settle down in a new aircraft type compared to one who is type-experienced.
KAL is not in the business of retaining anyone is is not up to their standard, regardless of experience level. Afterall, the rating is at your expense ... it doesn't cost KAL a cent. So if you are new on type, it's going to be tough trying to impress.