When applying for a social welfare contributory pension you must meet certain conditions. The first of these is, you must have 520 paid contributions. Once this condition is satisfied the credited and paid contributions are added together and the total is divided by the number of years which will have elapsed between the time of your first contribution and your final one. That to my mind is the real value of your credited contributions. However, the average will not be looked at unless the first condition is met i.e. 520 paid contributions.
Hope this explanation is of some help.