Knowing something about how a culture measures time tells us something about that culture, as long as we have a point of reference, that usually being the celestial movements that are visible from that world. Time is essentially a measure of the movement of celestial bodies in their orbits as seen from the home world, further broken down into calculated subdivisions based on a chosen numbering system or amalgam of systems. If we know the celestial movements that are observable from a particular world, we can eventually understand a system of keeping time.
Here on Earth, we currently use a roughly base-12 system of keeping time, with base-10 and base-60 elements. However, there have been a number of other methods of looking at the same phenomena and measuring them differently. The Mayan culture for instance used a base-20 system and had two separate calendars, one for the religious year, and one for the secular year. The religious year was 260 days in length (the cycle of Venus), while the secular year was 360 days in length, divided into 20 months of 18 days each.
Yet all earthly systems have at their core a day based on the rotational period of Earth, and a year based on the revolution period. If we had evolved on Mars (there is some anecdotal suggestion that we actually did�but that�s another story), our day would still be roughly 24 hours in length, but our year would be 687 days in length, giving us an average lifespan of about 39 Martian years.
Unfortunately, we the viewers do not have a point of reference for Galactica time, nor were we ever given a good translation matrix. How many centars in a cycle (day)? How many of those rotational periods make up an orbit (what is the length of a year in days)? Where did the system come from (who�s orbit)? How did it develop? As a star-spanning culture that had existed for thousands of �years�, the Colonial measures of time might have come down to them from Kobol where it might have evolved, or might have been born instead on one of the 12 colonies, and been adapted by the others, or was simply created when the colonies decided that 12 separate systems of time keeping was inefficient. Perhaps the 12 different systems were all based on the same one, but modified and adapted by each colony. Perhaps this change to a single system is relatively new, and that is why there are both separate pronunciations and occasional differences in meaning for various terms.
All of this is said to make a relatively simple point: Like a number of other things about the series, we don�t and can�t know how the Colonials measured time. We can speculate, and come up with possible theories, but without any hard information, theories are all we have. We therefore cannot make judgments as to the seeming inconsistencies we often see and hear in the series.