From a registration form the user sends last four of SSN

I I then run SPT and getting a SSN from remote database based on user ID

I am trying to compare these two but what I have tried is not working. It always shows a mismatch

Both are type 'C'

DO Case
Case AT(lastfour, sqlStringSSNQuery.ssn) lessthan 1
RETURN "NVDError"
EndCase