The D/C is an OBRA assessment. However, a D/C can never be a "prior assessment" because the only MDS record that can follow a D/C is an entry tracking record. You can no longer set an ARD and complete an assessment for a date after the date of discharge. If the resident admits or returns to the facility after discharge then the entry tracking record is your starting point.
The resident admits, or reenters, the facility and falls. On the 5-day, you set J1800 as yes for a fall.
If the resident does not fall after the ARD of the 5-day then J1800 on the 14-day would be no since the resident did not fall since the 5-day (the most recent assessment).
If the resident then discharges, you mark whether the resident fell after the ARD of the 14-day.
If the resident is readmitted, you complete the entry tracking record and start watching for a fall again as of the new entry date.