All batteries have a memory effect when unloaded such that they return slowly to near the previous voltage after a short burst load. There is also momentary quick drop in voltage due to a load of ESR*I = Δ V.
So both measurements must be taken at the same time to check calibration for errors and consider the amount of hysteresis thresholds required to prevent oscillation of sleep, wake-up cycles.
The memory effect time constant can be several to many minutes depending on the "no-load" leakage current after a load.
Because of these combined effects which might be computed for a given cell (ΔV= ESR * V/Rload + t/ESR * C2) the cut-off voltage is often lowered to capture the charge stored in memory capacitance C2 as long you know it returns to the safe Vmin threshold. Battery rapid aging occurs for the amount of time below its Vmin threshold.
Review the battery datasheet for details.