How shall the amount of support be determined, reduced or increased?
The amount of support, in the cases referred to in Articles 195 and 196, shall be in proportion to the resources or means of the giver and to the necessities of the recipient.
Support in the cases referred to in the preceding article shall be reduced or increased proportionately, according to the reduction or increase of the necessities of the recipient and the resources or means of the person obliged to furnish the same. (Arts. 201 and 202, Family Code)