Am I missing something या did Anderson make a big mess up in the time line when लेखन Afterlife?? According to the पूर्व movies&my math at the begining of the movie when it says "four years later" it should be SIX!!???

Alice makes it clear upon meeting up w/ clair again its been a साल and half sence getting the chopper in the desert. And when finding clair in alaska its six months after the attack on the जापान facility.so from this आप can see it took alice and her clones a साल to reach japan. If आप do the math w/ the first three films आप know its been 5years allready at the end of extinction.add a साल and आप got SIX!!!!??