I wasn't happy with the simple 1"=1000 feet altitude calculation method. Accuracy was crappy above 5000 feet. This version uses a lookup table derived from the Barometric Formula and maintains ~ 100 feet accuracy throughout its operating range. Also some other minor improvements to the user interface:

• Added timeout to version # display at boot to prevent situation where user changes battery and forgets to acknowledge.
• Added key-press inactivity timeout to setup to prevent battery drain.
• Added fast repeat to Setup to make large value changes go faster (kicks in when button press > 5 seconds).

The source is posted in the files section along with an updated workbook that contains the algorithm used to calculate altitude.