Clear Medication Instruction field on discharge instructions after visit

The system automatically clears medication next dose date/time from visit to visit on the discharge instructions. The system DOES NOT clear the medication Instructions field. Our facility places very specific instructions in this field that pertain to that specific visit and for those instructions to carry over to a new visit set us up for an error to happen if someone doesn't remove it from that field. Why does the system not function the same for all editable fields?