I am not sure if this has been answered but for future users, you can close out bulk purchase orders by following these steps:
1. Select the Vendors tab.
2. Select Bill Tracker.
3. In the Type tab, select Purchase Order.
4. In the Status tab, select Open.
5. Select P.O.'s you would like to close.
6. On the bottom left of page, select Batch Action (Close).
