The PASSID is tied to the individual and their status in the program. If you upgrade from Global Entry to NEXUS for instance, your KTN remains the same - even though you get a new document (a NEXUS Card) upon acceptance into Global Entry.

I think the SC is a security code like the three digits on the back of a credit card. It's been a while since I had to activate a new card but I think that was one of the fields asked for.

There are some other entries on the card, but the 10####### is almost certainly a document number. Western Hemisphere Travel Initiative standardizes the fields in the machine readable zone.

On my US Passport card it's
IPUSAC######## (where the #s match the "passport card no" listed on the front of the document that starts with a C and then is a series of digits).

On my Enhanced Drivers License it's
IDUSA########## (where the #s is a series of numbers and letters that the NYS DMV website explicitly says is the document number, and hasn't been listed on the front since 2014).

On my Nexus card it's
INUSA10######### (where the #s is the 10# listed on the right side of the card in larger print).

So I'm very sure that given these are all WHTI documents and the fact that the position in the MRZ is known to be the document number (that would change if a new document was issued due to changes in circumstance or loss/destruction of prior document) bears out that the 10# is the document number on NEXUS and GE cards.