Portable propane tanks are DOT tanks and require recertification.  The Westy
one is an ASME tank which does not require recertification, at least not
yet.  When your DOT tank is 12 years old, empty it and recycle it, the
ninnies in our current regime require a new overfill protection device or
OPD on all DOT tanks so the untrained masses don't continue to kill
themselves in large numbers by overfilling the old tanks.  It seems the
piles of bodies littering the landscape became offensive to the tank
manufacturers who lobbied the shrubbery to get the law passed, all in the
name of safety and security as is the fashion these days.  I have a local
purveyor who fills my tank.  The local purveyor near Kayenta AZ had no
issues with a nicely kept 15yr old DOT tank.  YMMV.