Am I missing something o did Anderson make a big mess up in the time line when escritura Afterlife?? According to the anterior 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 año and half sence getting the chopper in the desert. And when finding clair in alaska its six months after the attack on the japón facility.so from this tu can see it took alice and her clones a año to reach japan. If tu do the math w/ the first three films tu know its been 5years allready at the end of extinction.add a año and tu got SIX!!!!??