We demonstrate that the T-c value of superconductive copper oxides does not depend on the distance between two adjacent CuO2 planes as long as the hole-doping level and the immediate (crystal) chemical surroundings of the planes are kept the same. Experimental evidence is accomplished for the homologous series of (Cu,Mo)-12s2, the member phases of which differ from each other by the number (s) of cation layers in the fluorite-structured (Ce,Y)-[O-2-(Ce,Y)](s-1) block between the CuO2 planes. X-ray absorption near-edge structure spectroscopy is employed as a probe for the hole states of these phases. The s = 1 member appears to be more strongly doped with holes than other phases of the series and accordingly to possess the highest T-c value of 87 K. For s >= 2, unexpectedly, both the CuO2 plane hole concentration and the value of T-c (similar to 55 K) remain constant, being independent of s.