Maybe that's not the intention of Amazon, as these license terms probably standard license terms for digital content (such as music, etc.) are. This should be clarified in any case before buying, if you intend to use the software also commercially.
Here is an extract from the Amazon license terms:
"2.1 Grant of Rights. Upon payment of the purchase price for the digital content we grant you a non-exclusive, non-transferable right to private, non-commercial and non-business use of digital content in accordance with these Terms of Use."