I found it interesting on the PSA website that in their SMR Price Guide they have a note on the T220 page that indicates Tolstoi backs command a premium but there was no mention of Tolstois on their T218 page. As we know - the Tolstois are rarer in the T218 set. I sent them an email a couple weeks ago pointing that and they have since updated their T218 page noting the Tolstoi premium.
http://www.psacard.com/SMRPriceGuide...x?SMRSetID=634