FWIW, my child is in 4th grade at a gifted magnet and gets and has gotten straight As from the start. AFAIK, these are based entirely on tests, assignments, and HW--the teachers give out the calculations, like in a college class, occasionally. We did experience the "meets expectations" going up to "surpasses expectations" phenom at her previous school.

DS5 is in K and is getting the "meets expectations" grades.