A couple of years ago, I wrote some custom functions to help speed up working on estimates for our clients. Well, those functions have been lost since I left Classy Llama, but I think the these versions are much improved anyway.
Anyway, here are some Google Apps Script functions for Spreadsheets which might be useful for those in Technical Sales or software development. They can be used to add up and manipulate hour ranges (e.g. SUMRANGE(["1-2",2,"2-5"]) would yield "5-9"). Those functions are SUMRANGE, SUMRANGEHIGH, SUMRANGELOW, RANGEMULT, and RANGEADD.