Simple interface that does what it's advertised to do. Great idea'
3.1: Ability to set default values and/or remember last entered values for input variables. Added a new dialog to make editing variables easier. Improved preferences page. Optional calculator button to right of all variables on compute page. Option to show description at top of compute page. Improvements to appearance.
3.0: Bug fixes. Improvements to calculator tool. Added long press on variable to move it up or down. Added HH:MM format (as well as HH:MM:SS) for times.