There are loads of STCs for the Aspen and theirs is only one. Mine was installed under a different STC.
This is true on all major brands, Aspen requires Aspen dealers, so do Garmin, Avidyne, S-TEC, Rotax, Thielert as well as some aircraft brands.
Not strange in my opinion.
Under EASA removed equipment would also require a new form, which only can be issued by Aspen.
