There is another way. It also doesn't require you to 'extend' your 'time away' or lose your listings.

Just before you want to close...
1. Change your 'out of stock' option in myebay>seller account>Site preferences>Use out of stock option to 'YES'
2. Edit all listings to show '0' stock - all the listings will now become invisible.
3. When you return - edit all listings & return the stock levels back to what it should be.
4. Make sure to change your 'out of stock' option back to NO after editing stock levels - otherwise you'll pay for listings even without stock or showing.

Your GTC listings will still automatically relist while you're away - but with 0 stock (I think for 90 days-not sure about the time frame)