وأما القاصر: فهو ما لا يماثل الواجب صورة ويماثله معنى
Deficient qaḍāʾ is a substitute that does not reproduce the original form but corresponds to it in a legally significant respect.
For example, a particular goat that has been destroyed cannot usually be duplicated in all its age, health, condition, and other individual features. Its monetary value may stand in as a financial substitute, but it is not another identical goat.
The proper valuation date and conditions can differ across cases. A single unqualified rule about price at all times should not be inferred.