Hey I would have said for the question 15 something else, I don't say you're right I am wrong or vice versa.
This is my opnion.
1: there is nothing wrong with, all companys do it and it is only calculations, so again this in my opinion wouldn't be registered.
2: is saying it will state details in a "personal" adress book, who's book is this? It could be someone who works here, but knows the people, so they have their adress, the use of "personal" needs to be explained further, who's is this "personal" book? From where I see it this wouldn't have to be as it isn't going to be shared and I think wouldn't have to be registered.
3: However I feel would have to be registered. Because it is personal details that are being used for company pay roll purposes.
So as you see my answer to yours, would be... different to yours, whether that is right or not is something else, I am trying to shed the light you wanted, without giving a direct asnwer, as we're not suppose to in this forum, we can only assist.
This is my view and what I remember from studying the data protection act, and my own thoughts on the matter.
I hope this helps though.