Lieutenant-Colonel Steve Boylan said on Monday a further five would also face non-judicial punishment under Article 15 of the US military justice code, taking the total number of soldiers disciplined in this way to 23.
He declined to detail the sanctions. Article 15 gives commanders the right to order brief detentions of up to a month, the deduction of a month's pay, extra duties and the loss of rank.
Asked whether the command had taken into account complaints by the reservists that the fuel trucks they were asked to drive through hostile central Iraq were not sufficiently armoured, Boylan declined to comment beyond saying: "The soldiers' performances are all taken into account."
At a court martial, soldiers found guilty of refusing to obey an order can be sentenced to up to two years in jail.
Members of the 343rd Quartermaster Company, based at Rock Hill, North Carolina, disobeyed orders to take their unarmoured fuel tankers on a supply run from Tallil, near Nasiriya, in southeastern Iraq to Taji, just north of Baghdad, on 13 October.
Dozens of roadside bombs go
off in the country every week
They raised concerns about the safety and the condition of their vehicles and whether the convoy was getting adequate protection.
Dozens of roadside bombs go off in Iraq every week, targeting US convoys and putting the truck drivers and convoy guards who keep the army supplied in the front line.
Some relatives have said the soldiers believed they were delivering contaminated helicopter fuel. The US military runs about 250 convoys daily, involving up to 3000 vehicles, to supply and equip its troops in Iraq.
The commander of the company was relieved of her duties after the incident. Other soldiers carried out the 13 October supply mission, the military said. The 343rd Quartermaster Company returned to full duty on 11 November.