So only two of Sulla Faustus’ types have S.C. on them (426/3, 426/4a, and 426/4b). Both of these also honor Pompey with there types and suppress the name of the moneyer by using ligature. I wonder if we can’t connect that S.C. with the degree mentioned in Cicero’s letter to his brother:
On the 5th of April, by a decree of the senate, a sum of money amounting to CCCC sestertia was voted to Pompey for the business of the corn-supply. But on the same day there was a vehement debate on the Campanian land, the senators making almost as much noise as a public meeting. The shortness of money and the high price of corn increased the exasperation.
This is in the year 56BC. Notice the coin type above actually refers to the command over the grain supply. Here’s Broughton MRR II.211:
Of course numbers in manuscripts are always subject to corruption, but it seems likely that Faustus’ extra minting was because of this!
Cf also this passage from Dio:
The fact, however, that Caesar’s influence was increasing and the people admired his achievements so much that they dispatched men from the senate, on the supposition that the Gauls had been completely subjugated, and that they were so elated by their hopes based on him as to vote him large sums of money, was a cruel thorn in Pompey’s side.