From what we learn here in Greece from defence magazines (flight and space) they conduct more than 30 shots on the turret front with 120mm shells and AT missiles and air boblets on the turret to test the heavy roof armour. 5 120mm rounds were fired on the front and 2 were penetrate the front armour from the gunners sight, a known weak spot from Leo-2A4 that was tried to rectified in the A5 and A6 versions. it was suposed to be rectified by armour piece and maybe eleveting more th sight and close the hole that used for cables. the company said it would be rectified. the Greek army refuse to accept the ready made tanks until the problem solved. that was done in september 2006. it was publiced in january 2007 in defence magazines. more thests were to be conducted in january 2007. i dont know other info but eventually greek army accepted the tanks so they reach some agreement.
update:
the problem was solved by adding extra plate of armour in front of the gunners thermal sight weight of 192kg, and probably they raised the sight a bit. more firing tests were folowed and were succesfull on april of 2007 and the delivering protocols resumed in october. mean wile new problems occure in 2008, hair cracks were developed arount the turret hatchets becouse of the extra turret armour stress in the roof in some tanks, and also peeling of the internal of the guns in some others. again the issues were resolved with measures taken. also the standard tracks of the tanks were insuficient for the 62 ton of the A6 model and already have tear, they were replaced by the stronger "mountain terrain" type in all tanks.
