Can’t say if you’re right or wrong. I just don’t know what you mean by “surplus contributions.” WHAT is surplus? That word would indicate that everything contributed by employees/employers is over and above what is needed to pay out benefits IMO. Clearly that is NOT the case with SS.
I am led to believe that currently the Social Security contributions coming in to the system are greater than the cost going out in benefit checks and administrative costs. That is what I am referring to as the surplus contributions continuing to be spent by Congress.