Stock Reconciliation - stock adjustment clarification

What does it mean when i get a negative difference amount in Stock Reconciliation - stock adjustment? How does this affect my profit and loss statement?

Simple logic is : If you have less stock than what your system says, you write off i.e. Loss in the P&L.
Else you gain in your P&L.

so the so called (and obligatory in “Stock adjustment” account is an expense account then?