I have a spreadsheet on my desktop to track and plan for BA TP and Hilton HHonors. Dropped the VS and KLM columns given the business travel element has dropped off.
Why use a complicated app when a simple spreadsheet is easy to change and update? There is where BAA went wrong with T5 by over-engineering with technology some of the simple operational stuff.
If you must, there are loads of spreadsheet apps for the iPhone