Hyponatremia in presence of severe hyperglycemia in DKA is real unlike spurious hyponatremia as seen in paraproteiemias/hyperlipidemia etc.
The measured Na is used to calculate the anion gap which is important in acidosis but the corrected Na is indicative of the amount of dehydration present.
The lab should not report just the corrected Na because it will create great confusion clinically. But if the lab wants to report both corrected and measured that might be useful.
But again 1.6 as correction formula, have we validated that? Some authors suggest 2.4 as correction factor performs better(Hillier T et al. Hyponatremia: evaluating the correction factor for hyperglycemia. Am J Med 1999; 106:399–403). I believe its best to report the measured one and leave the correction in the bedside on a real time basis.