Here are somethings we found out about sheet metal. Start with sheet metal, not extrude part.
The sheet metal feature should be used in the same fashion as a fillet, always done last. When adding features (holes or flanges) scroll back prior to the bending process. Add holes after the bending will not be part of the flat pattern. Remember to create the part as the fabricators do. Punch out the pattern and holes, bend the part and add Pem parts last. Bradley