The NPCs are in no way a guarantee, so there is nothing to ‘honor’. The school has no way of knowing if you put the information in correctly, if your asset situation changed since you did the NPC, if things at the schools changed (tuition increase, change in merit scholarship requirements) from the prior year.
The NPCs are often not up to date, especially in Aug and Sept when the tuition just increased and will increase again before your child starts school the following Aug or Sept.