In this paper it is considered the physical meaning of proper times, time dilation, Lorentz-FitzGerald contraction and distance, time ageing, time dilation-like and the twin paradox conundrum. Connected to the concepts of simultaneity and synchronization, that has also been addressed in other previous papers based on the existence of a Preferred Frame (designated by Einstein Frame, EF) - where the one-way speed of light is isotropic with the two-way value c. Usually in the standard Special Relativity what is considered is Einstein simultaneity and Einstein synchronization that has been introduced by Einstein in the 1905 article "by definition". In the standard interpretation simultaneity and synchronization are not considered since the Einstein speed of light is considered the speed of light. However, in our previous work we have shown that this is a terminological confusion, a paralogism. Now, we show, through a designated time ageing mathematical expression, that the time dilation expression only is the relation of the ageing of the twins when one of the frames is the preferred frame. Time can be dilated or contracted, and naturally the ageing is the same when the velocities of the twins are symmetrical in relation to the preferred frame. A similar relation is established for the distance mathematical expression that is only the Lorentz-FitzGerald contraction expression when one of the frames is the preferred frame. This analysis is related to the problem of the formulation of distance in the context of acceleration in the twin paradox conundrum. Therefore, it is explained why this is so with a very simple concise formalism using two clocks in every point of a frame, frame that is moving in relation to the Preferred Frame, a synchronized clock, and a Lorentzian clock. The non-equivalence of the frames emergewith physical meaning through the analysis of the Lorentz-FitzGerald contraction and Larmor time dilation mathematical expressions. Therefore, the twin paradox conundrum can be resolved in the context of the formulation of Special Relativity.