Car seat out of date?

Can someone please help me with this? I dont know how to read the out of date section on my sons car seat. Its australian standard infa secure. It has no shoulder lables. Manufacturer date says 2010-9-30. I think the out of date says 10th day of the 9th month 2016? Sorry if i sound stupid i just want my son to be safe!! Also i tighten the harness but it will sometimes loosen on its own and will fall down his arm passed his shoulder!! I will be getting a new car seat hopefully today