I think I see what you mean. I'm probably confusing the concept of free space for new rows (defined with FILLFACTOR) with new space for existing rows. Please check to see if my thinking is right.

If my clustered index's fill factor is set to 80% then 20% will be free for new rows. Adding a new column will not use that space and the page needs to be split to acomodate the new column but also the 20% free space will need to be kept. Would that be correct?

Thank you for all your help.

@sqlzealot-81: Thank you. I will take a look at that article. I'm still thinking if PERSISTED computed columns are worth using. 🙂

Best regards,