Re: frozen value for discrete animation

Yes, would be fine to have this as an additional
informative example in the specification for
keyTimes 1. It is not really needed to change
the specification. keyTimes 1 is only not very
useful for discrete animation, but these 
exception rules define the behaviour and
such an example points out, how the correct
behaviour is, if keyTimes 1 is used.
The described behaviour is as I expected for
accumulate none/sum. 

The other interesting/informative example results 
from an additional end at 15s or a max of 15s or a 
repeatDur of 15s or a repeatCount of 1.5 for the 
this example.
And I still think, the result is different in SMIL2
from the old SMIL animation recommendation or
from SVG behaviour because of new specific
exeptions in SMIL2 from the interval timing model,
I could not find in the old SMIL animation 
recommendation, and a slightly other definition
of the fill attribute.