Not really distinguishable for a receiver of merits or for an outside observer, but a merit source can see how many source smerits and earned smerits they have and the source smerits get sent first. So the merit source knows which ones are being used on a particular post... not sure if that really matters though (in this context). I think a merit source should uphold a higher standard regardless of which smerits they use. As opposed to non-source merit senders who can do almost whatever they please with their earned smerits.