Also, coffeefet is onto a looser here, because page 13 of the FSCQ1565 datasheet says that adding the drain_source capacitor is good for EMC.
This just is not correct, because it worsens EMC due to the fact that when the FET turns ON, the drain_source capacitance is suddenly discharged, resulting in a discharge current spike which worsens EMC.
The datasheet says that the slower rising drain voltage at FET turn-OFF reduces EMC problems, but it doesnt , because it worsens EMC at FET turn-ON time. You cannot reduce EMC problems in a flyback by simply adding a drain source capacitance....if only life were so easy.