You'd only find an Ordnance Sergeant in a fortification or permanent camp; not on campaign. And the QM Sergeant would be with the wagons and stores so, it wouldn't much matter on a battlefield. Only in an oddball occasion would either be there. These ranks are mostly reenactoisms.
"Grumpy" Dave T.
"Yet, despite these small numbers, Kernstown was one of the most decisive engagements of the war. The Confederates, Under Jackson, though soundly defeated, ultimately lost the most. As historian Bruce Catton observed: ‘The victory meant nothing at all, whereas the mere fact that the battle had been fought meant a great deal.’ Indeed, the ramifications of this odd little affair reached all the way to President Lincoln."