Merit sources should do their best to keep their available source merit close to zero (ie spend all their source merit), and doing so is not always easy if they do not read a lot of good posts. This means they may need to send a lot of merit per post.
No punishment to merit sources if they don't use all sourced smerit so they should not force themselves to send sourced smerit more than a post deserves to get.
1, 2 or any number can be sent to a good post but each source can bind with their rules. If their rules are.
Good post: 1 merit
Above good post: 2 merit
Excellent post: 3 merit.
They can bind with their rules. If is not fair if they send 1 merit to a good post usually but when their source is full, they send a good post 10 merit.