clarification sought on feComposite

Both IE/ASV and Opera appear to pass the tests in the test suite

 

However, the two come up with quite different impressions of what to do with

http://cs.sru.edu/~ddailey/svg/feComposite1.svg

 

The differences can be compared at

http://cs.sru.edu/~ddailey/svg/feCompositeCompare.jpg 

 

(Opera on top, IE/ASV underneath)

 

What differs between this test and the testSuite is the use of transparency
in the BackgroundImage. Magenta and cyan are partly transparent, while
yellow is opaque.

 

I have always assumed that IE/ASV did it right as per the Primer's treatment
:

 

http://www.w3.org/Graphics/SVG/IG/resources/svgprimer.html#feComposite

 

I'm about to finish up another elementary treatment of filters and I wanted
to verify that my thinking is correct here.

 

Should something like this example be added to the test suite?

 

Thanks in advance

David