Valades or Macias Valades?

I have been studying the Macias Valades family, and have found this family which is causing some confusion.

Juan Valades (1st) m. Maria Rebollo (or Lopez Rebollo) and had at least two children:
--Juan Valades (2nd), no baptism found, but I estimate his birth as 1646/51, most likely in Aguascalientes
--Nicolas Valades, baptized 24 Jul 1652 in Aguascalientes

Juan Valades (2nd) married twice (1) Nicolasa de Castaneda, 23 Feb 1671, Aguascalientes and (2) Maria Romo de Vivar, 4 Feb 1690, in Aguascalientes.

By (1) Nicolasa, he had
--Juana Valades, buried 11 Jun 1743, in Aguascalientes, wife of Miguel Altuna

By (2) Maria, he had
--(i) Joseph Manuel Valades, bapt. 20 Apr 1694,
--(ii) Isidro Valades, bapt. 9 Jun 1700,
--(iii) Juan Valades (3rd), bapt. 16 Dec 1702, and
--(iv) Joseph Joaquin Valades, b. abt 1620, and who married Maria del Carmen Jimenez, 29 Dec 1744. All baptisms and marriages are in Aguascalientes.

(iv) Joseph Joaquin Valades and Maria del Carmen Jimeenez had a daughter, Maria Antonia Valades, who married Jose Antonio Zermeno on 13 Jul 1768, in Aguascalientes.

The baptismal and marriage records consistently use only the surname "Valades," but there are some posted genealogies that use the surname "Macias Valades," but provide no explanation. They also do not go further back than Juan (1st) Valades.

I cannot yet place Juan Valades (who m. Maria Rebollo) anywhere as a descendant of Blas Macias (or Macias Valades).

Can anyone offer any insight?

George Fulton
Pleasanton, CA