T.E.C. date - the date of predicted Threshold Exceeded Condition (T.E.C.) for current attribute, i.e. it is a rough estimate date when attribute value will drop below its threshold.
Active SMART uses special algorithms to predict the date of the T.E.C. for every S.M.A.R.T. attribute. To maximize accuracy of the date prediction Active SMART shows the T.E.C. date for attribute only after two changes of it's value. It allows us as much as possible increase the date calculation accuracy. Note: This date is not an exact drive fail date, it's only estimated date and it should be used only as advisory data.