[@The Spectre][quote=@FrostedCaramel]
A Platoon Leader is the Officer in charge of a single Platoon, normally they get orders from Company Command and disseminate it to their Squad leaders who disseminate it to the men on the assault.

Company Operations Sergeant is the NCO in charge of the Company level stuff, so lots of Paperwork and likely advising the Company Commander on tactics and strategy in combat situations.

One is an Officer in charge of less people, one is an NCO "in charge" of more people.[/quote]
FrostedCaramel is correct about the PL being an officer. 2nd Lieutenants and 1st Lieutenants occupy this slot in a platoon. I am aware the US Army used Operations Sergeants during World War II and later. They are not used today, but the USMC do use them today. The ranks during WWII were very different than they are today and were only used from 1942 to 1948. The authorized rank for an Operations NCO (Non-Commissioned Officer) is Technical Sergeant (3 stripes and 2 rockers), but could be occupied by a Technician 3rd Grade (3 stripes, one rocker and a "T" in the middle). The Technician ranks were only used during WWII. After the Air Force split off in 1948, the Army dissolved them, then later included the Specialist ranks which were used during Vietnam and then eliminated again in 1983.

I know that can be confusing. I've been studying milhist for over 42 years. 

The benefit of starting with the lower rank, is your character can be promoted during the RP. That is why I chose a 1st Lieutenant for the Company Commander.

NOTE: there are no infantry fire teams used during WWII. That structure was used sometime after the Korean War era. I know they were used during Vietnam War and later.