Oklahoma City keeps Central Time, UTC−6, an hour forward from the second Sunday in March to the first Sunday in November. India is ten and a half hours ahead in summer and eleven and a half in winter, so a planner's 08:00 question arrives at 18:30 or 19:30 IST, as an Indian plant's day shift ends.
That makes the evening the hour that counts. A supplier who keeps one person on until 21:00 IST can answer the first part of the Oklahoma City morning inside the window the question opened; anything later is answered when the Indian day starts, still inside the window, while the hangar sleeps.
Templates are not bound by any of this. A dispatch notice can leave the moment the parcel is booked in Bengaluru, at whatever hour that is in Oklahoma, and be waiting when the planner arrives.