Is saving a quantity of completed work in excess of the daily "target" to submit on days when achievement is low considered deceit? Is the money earned from this work unlawful (haram)? And what is its expiation if it is?

The default is the obligation to fulfill the contract. Therefore, the employee is required to enter the agreed-upon number of papers daily, and it is not permissible to delay them until the next day, as this involves hindering work and lying. However, if this does not cause harm to anyone, and the employer is oppressive, then in this case, it is permissible to delay them, and the lying here is excused because it does not result in harm.

Scholars have differed on the permissibility of combining time estimation and work in a contract, and the more preponderant opinion is that it is permissible, which is how people operate today, provided that the estimated duration is reasonable.