When excel appears different from what you learn in class....
DO NOT GO WITH EXCEL. It has some things that are wrong, that will confuse you and you'll start wondering which is right, changing your definition of things and it'll mess up your whole system and screw you over. My suggestion is if you find these, you should pour oil on these pages and burn them, and preferably have them erased from your memory if possible.
You could go with excel, but for that reason id recommend macquarie, but the heinemann textbook is good enough for IPT, really.
The revise in a month one is pretty good though - actually applies your knowledge.
EDIT: From what I've seen of the new ones, the errors corrected.
However, Heinemann is the best.
I didn't really like the Cambridge textbook at all but some think its good.