The poll and precision fields in timing NTP messages are signed integers.
Different NTP implementations have different minimum and maximum polling intervals. Some can be configured even with negative values for sub-second intervals (e.g. down to -7 for 1/128th of a second).
NTP clocks on modern systems and hardware typically have a sub-microsecond precision.
Print all poll values. Add the raw precision and change the resolution of the printed value to nanoseconds.