When I went on active duty in 1969, I went in as a 1LT having delayed entry for grad school. 12 moths later I was a CPT. My contemproaries who entered as 2LTs were 1LTs in 12 montha and CPTs 12 months later - 24 months to CPT. In wartime promotions always accelerate and decelerate in peacetime. This is not to say it is a good thing, just that it always happens and could be worse.