I regularly went below 200 in VIIs both B and C, VIIc as deep as 225 without troubles except my own nerves.
Today my IXb was in an unstoppable dive to the bottom stern first while filling with water and both electrics out of comission I made it down to 350 meters before imploding even though the depth charge that blew my electrics to bits exploded right near the hull
so know I know I can take my IXb to 250 if I really need to, this is a good thing
U-boats are tough, what US subs can take in feet they can handle in meters (almost)