Tip is calculated on Total instead of Sub-Total

[GoogleCodeExporter]

What steps will reproduce the problem?
1. totals add up to 69
2. tax is 10
3. tip is set to 10% for calculative purposes.  ;)

What is the expected output? What do you see instead?
6.9, i see 7.9

What version of the product are you using? On what operating system?
firmware 1.1.1 on iphone, version .981beta-1

Please provide any additional information below.
Very nice application.  :)

Original issue reported on code.google.com by rch...@gmail.com on 15 Nov 2007 at 8:44