Yes, merit is not to be updated but it should be acquired after doing something good to others that could be merited. This is one way of acquiring merit. But, for now it seem so hard to acquire merit unless you reached to a certain level of expectations to the merit source.

I guess there is a protocol on giving merit and for sure it composed of the time or the days you were here in the forum (not really sure for this) and the number of your activity though it is not stated in this forum. It is a discretion of a merit source in giving merit. But, it will not only matter on this for it is in the uniqueness of the posts they consider to award merits.