you can enter a week before it expires get stamped in for 60 days plus extension for 30 days so effectively you can get extra say 83 days past the expiry date if you enter before it expires
Arrive get 60 days extend 30. Go to nearby country come back get another 60 days plus extension. Then a week before your 6 month multi entry expires leave again come back get 60 plus 30 again. You just need to keep an eye on the expiry date of the visa to milk the most time from it