The document in question was his surrender document, 1.5 years after he deserted. It was his explanation of when and where he left the unit (18th Battalion Mississippi Cavalry), whose movements and actions are fairly well documented. The place and date he gave was the first action of the unit, guarding a major river ford while the rest of the brigade attacked the Union garrison at Collierville, TN, about 20 miles away.

Seems pretty cut and dried.