A beneficial impact of the fat quality on insulin sensitivity is not seen in individuals with a high fat intake (> 37E%).
This is likely do to the reduced carbohydrate intake rather than increased fat intake. Since carbohydrates generally insulin sensitivity, it's likely that this additional insulin resistance is acting as a confounder (as well as, presumably, a standard deviation widener). Thus, I would expect similar results during hypocaloric carbohydrate restriction.