'Upgrade' editions are the discounted versions of the software for users who already have an earlier edition on their PCs. The move will effectively raise the price for many users who want to migrate from older editions of the popular suite.
Microsoft also spelled out prices for its new 'key cards' or single-licence codes that will be sold at up to 30 percent off boxed copy prices, for upgrading the Office Starter 2010 mini-suite that many computer makers are expected to preinstall on new PCs.
Finally, Microsoft has trimmed the number of retail editions of Office 2010 for the general public to three, down from Office 2007's five.
The boxed version of Office 2010 Home and Student, which includes Word, Excel, PowerPoint and OneNote, will cost $149 (about £92) in the US, and lets a family install the suite on as many of three household PCs. A single-licence key card will cost $119 (£75), 20 percent less than the boxed copy. UK pricing has not yet been revealed.
Office 2010 Home and Business, which adds the Outlook email client to the four applications available in Home and Student, is $249 (£155) and can be installed on up to two of the buyer's PCs. A one-licence key card will be priced at $199 (£123), a 20 percent savings.
Adding Publisher and Access, Microsoft's desktop database software, Office 2010 Professional will be priced at $499 (£310) and can be installed on a pair of PCs. The single-licence key card, however, will cost $349 (£217), a discount of 30 percent.
Microsoft is making changes to more than the suite's editions, however. A company spokeswoman confirmed today that Microsoft does not plan to offer separate upgrade editions for Office 2010.
That's a major departure from the past; Microsoft has traditionally sold upgrades at prices significantly less than the so-called 'full' editions, which are designed for installing the suite on a PC sans Office.
New with Office 2010, Microsoft's product key card - a small credit card-sized piece of plastic that includes a single licence activation key - is aimed at customers who have purchased a new PC with Office Starter 2010 preinstalled.
Starter, which replaces the decades-old Microsoft Works suite, includes reduced functionality versions of Word and Excel, but lacks the PowerPoint and OneNote applications available on Home and Student.
All the codes for Home and Student, Home and Business, and Professional are installed on new PCs that offer Officer Starter; the key simply 'unlocks' the appropriate version, eliminating the need to download additional software.
Office Starter will include on-screen advertisements in the lower-right-hand corner of the Word and Excel windows; those ads, of course, vanish when a key card and its product activation key are used to upgrade to one of the paying editions.
All versions of Office 2010 also come with Office Web Apps, the bare-bones online Word, Excel, PowerPoint and OneNote applications that consumers can use for free via Windows Live and enterprise workers can access if their companies have an Office Software Assurance Plan.
Office 2010 is scheduled to debut in June. The Microsoft spokeswoman said that the company would offer a promotion at some point before its release that will give buyers of Office 2007 a free or heavily-discounted copy of the new Office 2010 when it launches.