According to the note in the user's manual (Specifications, Table 2), why does TOS7200 require a 1.0 s wait time for LOWER judgments below 200 nA?

When measuring extremely small currents such as 200 nA, a wait time is necessary to ensure a stable and accurate measurement condition.

According to the note in the user’s manual (Specifications, Table 2), why does TOS7200 require a 1.0 s wait time for LOWER judgments below 200 nA?