It wouldn't be necessarily calculated in a different manner, I would say. It would simply be giving greater precision in the act so that sentence calculators are able to ensure that day parole eligibility dates and full parole eligibility dates are clearly laid out in the legislation. The calculation would remain the same, but experience demonstrates that the current provisions of the act were rather unspecific and unclear in some cases when there were multiple sentences at play.
It is trying to give greater specificity and precision to those clauses; the practice would essentially remain the same.