You're correct. Per Alabama state code, the term of imprisonment for a Class A felony is "for life or not more than 99 years or less than 10 years." Presumably 99 years is given by the state as the functional equivalent of a life sentence; perhaps having the number alters how parole works with one or more sentences. We used life in this article because it seems to be what the sentencing guideline has in mind more than a number of years, but perhaps some writers believe there is more shock value in saying "99 years."