This PmTimeDate reports when the current sample interval will close, per its DESCRIPTION, the short-cadence counterpart to IntervalEndTime. This is the timestamp that tells you when the next individual sample reading (and thus the next opportunity for that sample to register as an overflow or underflow condition) will actually be taken, which is a much finer-grained event than the end-of-Adjustment-Interval evaluation. For example, if this reads two minutes from now, an operator watching a metric that is currently hovering right at the overflow boundary knows the next data point that could tip it into an overflow condition is only two minutes away.