BO16 (Price and /or Order Depth Information) has no field for Timestamp.
Holdback timer is a specification which accumulates the fluctuation of price occurred for a period set to Holdback timer and outputs the information according to the holdback timer configured.
Please note that Holdback timer is set to 100ms for BO16 (Price and /or Order Depth Information) and 2000ms for BO17 (Price and /or Order Depth Information).