Have you requested this recently? SC is NOT available for purchases insured over $500 at least with USPS. You cannot add this option at the PO or online. They completely removed it. I talked to a a supervisor at my PO and he said that if you wanted an electronic copy of the signature, you can now request it (for eBay/pp cases). I know before, the signature that comes with the insurance wasn't viewable/you couldn't request the electronic signature as proof. In addition, before if you just insured, even though at a certain point it does come with a "signature", the tracking online would just simply say "insured" but nothing about a signature. Now, with the new change, if you insure over $500, the tracking online actually says "insured" and "signature confirmation". So the PO won't sell OP SC because it's redundant. And I believe, that so long as the online tracking says "SC" you're covered by the eBay/PP seller protection.