Where the land registration tax does not take the place of registration duties, only one proportional tax is payable, in any event, on the main deed and on the deed supplementing, interpreting, rectifying material errors, accepting or waiving outright, confirming, approving, homologating, ratifying or fulfilling a suspensive condition.
Deeds exempt from the proportional tax by virtue of the provisions of the first paragraph shall bear the fixed tax if their publication is not required at the same time as that of the deed subject to the proportional tax, unless they contain an increase in the prices, values, sums or claims expressed, stated, assessed or guaranteed, in which case the proportional tax shall be levied only on the amount of such increase.