"Adding up the Benefits" is an English language marketing phrase in which I think the "adding up" is an echo of the more common "piling up." The phrase is used as a headline as it is used in your example. I think that from a marketing standpoint the target audience is supposed to get a mental image that the benefits keep adding up, or keep piling up.

It is not merely an way of saying. here is the adddition of, or the list of or something like that.

HERE ARE A FEW EXAMPLES:

Adding Up the Benefits of Calcium
Calcium, the most common mineral in the body, plays an essential role in blood clotting, muscle contraction, nerve impulse transmission, and bone and tooth formation.

Studies indicate that calcium plays a role in blood vessels contraction and dilation which effects blood pressure. Also, the role of calcium in helping with weight control appears is promising.
(AND IT GOES ON TO DESCRIBE MORE ABOUT CALCIUM AND ITS BENEFITES)
http://www.yalemedicalgroup.org/stw/Page.asp?PageID=STW00029...

The conference theme is Adding up the Benefits. Workshops and presentations
will feature research and real-life examples that show the benefits of plain
language and design in government, business, health care, and the professions.
Participants will learn how plain language can reduce costs, increase client
satisfaction, and improve compliance.
http://www.plainlanguagenetwork.org/conferences/2005/FinalPr...

Adding up the benefits.
Using Autodesk BIM software,
Mortenson Construction delivers
construction projects faster and more
cost-effectively.
http://images.autodesk.com/adsk/files/navisworks10_custstory...



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Note added at 1 hr (2011-03-21 18:40:53 GMT)
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Here is a similar one from M.I.T. I think if you look at any of these links you will get a good sense of how the term is being used.

Adding Up the Benefits
Extending automation into the finance
department provides strong functional and
business benefits and unlocks the very
real potential for future enhancements.
As a result, CFOs will be able to realize
immediate and sustained cost savings,
as well as having the clarity to optimize
business processes and maximize
investment opportunities
dspace.mit.edu/.../Auto%20ID%20_%20page%2038%20_%20Datta.pdf?...