if you delete your post, sender should be refunded. it means that you didn't want the merits, they could be used for others actually wanting those merits.
Great. And how exactly would this work, considering the one receiving the merit would also get sMerit? Or will you let them keep the sMerit? That would lead to a lot of merit farming.
Will you cut off the chain of merit being sent out? Then that wouldn't be fair to the ones who actually have good posts and were sent merit from the chain extending from the deleted post.
If the merited post was deleted without the moderator consent, then the Merit and sMerit should returned to the meriter.
If someone want to delete their merited post they asked the moderator for approval, if not the moderator well returned the merit and sMerit to the meriter to continue search meritable post.