Subject to §2260.005 of the Texas Government Code, the procedures contained within Chapter 2260 of the Texas Government Code are exclusive and required prerequisites to suit in accordance with Chapter 107 of the Texas Civil Practice and Remedies Code. Chapter 2260 of the Texas Government Code does not prevent a contractor sued by a unit of state government from asserting a counterclaim or right of offset against the unit of state government in the court in which the unit of state government files the suit.