Application of deductions in the personal income tax return
The deductions reduce the differential rate, regardless of whether said differential rate is positive or negative. Consequently, the amount of the deductions that must be applied must be stated in the declaration for the year in the section corresponding to "Differential fee and result of the declaration", of the declaration model, boxes [ 0623 ] for the deduction for dependent disabled descendants, [ 0636] for the deduction for dependent ascendants with disabilities,  for the deduction for a non-legally separated spouse with a disability, [ 0660 ] for the deduction for large families and [ 0662 ] for the deduction for ascendants, separate legally or without marital ties, with two children without the right to receive annuities for maintenance.
Note: The descendants or ascendants and the non-legally separated spouse with a disability who are related to the deductions for dependent persons with disabilities must have NIF .
Taxpayers to whom, because they had requested it at the time, the Tax Agency had paid monthly amounts as advance payment, must enter the sum of these, depending on the corresponding deduction, in boxes  (deduction for dependent descendants with disabilities),  (deduction for disabled dependent ascendants), [ 0249] (deduction for non-legally separated dependent spouse with disability)  (deduction for large family) and  (deduction for ascendants, legally separated or without marital ties, with two children without the right to receive annuities for maintenance) from statement .
Likewise, when amounts have been collected in advance and the taxpayer, in the case of dependent people with disabilities, does not have the right to the minimum for descendants or ascendants, they must regularize such situation in their declaration for Personal Income Tax entering in boxes  or  , as appropriate, the amount collected that must be regularized.
In the case of taxpayers not required to declare , such regularization will be carried out by depositing the amounts received in excess in the place, manner and period determined by the Minister of Finance .
See in this regard Order HFP /105/2017, of February 6, which approves models 121 and 122 ( BOE of 10 ).
Note: Default interest will not be payable for the receipt, through advance payment and for reasons not attributable to the taxpayer, of amounts greater than those corresponding to deductions for large families or dependent persons with disabilities.