Recently I bought this byzantine follis. I believe it might be Heraclius follis, minted in Constaninopole (2nd officina), overrstruck on Maurice Tiberius follis, minted in Constantinopole in 6th regnal year i.e. 586/587. In other words I think it's SB 805 overstruck on SB 494. I would be absolutely grateful for any opinion about this coin.
Since you have no other answer after a day I'll just say I list these (worthpoint example of mine below from past auction) as "Heraclius 610-641AD with Heraclius Constantine Overstruck on other Follis ". But yours has the obvious TIB and of course your coin is struck over a Maurice Tiberius.
I love these byzantine overstruck coins, it's always a bit of a challenge and mystery. Usually I list them in a similar way as you. And I must say that your purchase is also absolutely great, especially the right coin (with weight 14,93 g).