Here, applying the lacking part of ultimate theory, i.e. the Scale-Symmetric Theory (SST), we described phenomena that lead to an illusion of acceleration of expansion of the Universe for z > 0.45 and of deceleration for z > 0.60. We cannot neglect both the perturbant/”gravitational” redshift for z > = 0.53 and the duality of relativity. The derived formulae for time distance between source and observer, give the time distances greater than calculated within the mainstream cosmology (for z = 0.45 is about 30%). On the other hand, the distances of the Type Ia supernovae were, on average, 10% to 15% farther than expected. This means that the Type Ia supernovae are fainter than they should be not due to an acceleration of expansion but due to inaccurate formula for time distance applied in the mainstream cosmology. Correctness of the new formula follows from the fact that calculated maximum redshift is z = 11.9. This value is consistent with the present-day observational facts (the maximum is z = 11.8 +- 0.3 for the candidate protogalaxy UDFj-39546284). Due to the duality of relativity and due to the perturbant/”gravitational” redshift for compact cosmological objects, it is very difficult to calculate within the mainstream cosmology the exact time distances to the Type Ia supernovae. The uncertainty is much higher than the assumed about 5%.