You are mistaken my friend.
Unlikely, let's call it "misunderstood" 
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Merit spent when you have available source merit comes from your source merit balance, not your sMerit balance.
I meant you were out of sMerit before you were a source, then you started sharing more, which much mean you're a source now.Quote
I am not sure if most merit sources spend more than their source merit each month
The total amount of sMerit transfered is very close to the total amount that sources have to spend. So not all sources empty theirs.