I encountered two costly problems with sheet metal recently SW2011 SP5:

If a hole diameter is changed in a bent part, it fails to update in the flat pattern.The only solution I found to this is deleting the flat from drawing and part and adding it back in again. My VAR is checking if this is cured in 2012 but there is an oustanding SPR which mentions it and says it isn't, though it is customer critical (thats one version upgrade and at least 5 service packs ago). If anyone knows a way to force the flat pattern to recognise the edited holes please let me know.

Second is the bend allowance setting. This uses whatever you used last, and cant be set in the part template as a template has no features and sheet metal doesn't exist until you create some sheetmetal. Workround might be to put sheet metal in your template with the settings you want, and then delete or edit that feature every time you start a part. I'd like to set the sheet metal defaults in a template please. It seems after upgrade from 2010 to 2012 bend allowance became set to "bend deduction=0" on my system and a all the flat patterns I did for a couple of months are wrong - and bend deduction=0 is an impossible scenario in the real world, so why is it even available?

If anyone knows a way to fix the sheet metal parameters for new parts please let me know.