that seems too long. puncture w a fork
i do potatoes 'dry' but that's up to you i like a seriously dry and crunchy skin.
I micro the potatoes for a few minutes first to get them going
Id say, dry, fork'd 450 steam bake < hour , more like 50 min.
do more than one. the extra you either eat right then its gong to be so good
or save for HomeFries in the AM.
chop up, season to your liking add butter or oil
steam bake 20 minus or so
then steam-broil for extra color.