If investors could enter only on fixed dates and could neither add nor withdraw funds during the term, modern deposit accounts would be extremely difficult to operate. Daily products seek to accommodate changing balances while retaining actual profit-sharing.
This is a proposed modern application and not an uncontested classical formula.
For banking practice, the rule must also be workable in accounting and monitoring. The aim is to preserve genuine risk-sharing while using a method that can be audited and applied consistently.
The method is presented as a modern application requiring careful juristic consideration.