Was this an actual grading company or more of a dealer who instead of flips used slabs instead? See here: https://www.ebay.com/itm/155179761853?
Here is a thread that covers them https://forums.collectors.com/discussion/852452/hannes-tulving-slabs
I remember Tulving from the 80's. At large shows he was a character. A few dealers asked for different tables if they were next to him. He was known for his mood swings as well. Bought four clipped Ikes from him. Gave me a decent deal on 3 double row boxes of world crowns.
Tulving was arrested for fraud in 2016. https://www.justice.gov/usao-wdnc/p...metals-dealer-and-his-company-defrauding-over