For example, I want to send you a merit then it will take my smerits and once you receive 1 merit you will get 0.5 smerit. For every 2 merits you received you will have 1 smerits. In your case you got 4 merits then that means you have 2 smerits in total if you haven't send your smerits to anyone who you want to merit by sending your smerits to that person.