If there are two or more students in a family,the summary of budget measures states that the higher student service charge (€2000) will only apply to one student in a family at any one time.
Tax relief is now allowable on the Student contribution charge, but the first €2000 (for full-time students) is disregarded. This means that tax relief is available on the second and subsequent student's contribution, up to a maximum amount of €7000.
Nuig are charging €1500 for the second and subsequent student,
BUT
UCD seem to have taken a different view of the budget changes and they are charging €2000 for each student in a family.
I don't know what other colleges are charging.
(I had links to the Budget Summary, to Revenue tax relief, to NUIG and to UCD student contribution charge in this post, just in case they were of any help to someone, but because I have less than 15 posts, I am not allowed to post them)