Hi Marjorie
We had big problems with the output from ActivExpression not being adequate so we looked around and found a way (using VBA) to count colours in particular cells. I tried to attach the files we use but can't - probably because they're Excel and some macros are bad news! Try searching for ColorFunction Excel VBA on the web and hopefully something will turn up for you.
We incorporated the colour count function into a macro which gets rid of all the peripheral cells that don’t contribute anything useful and the result is an output that counts the green cells (hopefully – if the student you set in the colour count formula gets it correct!) and then gives you a total score for that particular test. We ignore the % field next to it and calculate our own in a different worksheet. The Cell Reference is the total Raw Score we get from the Colour Count and the percentage is calculated from that.
As the formula says – Cell C2 uses the ColorFunction (that code I talked about) and looks at Cell $F$2 every time (luckily this student got it right – if not just change that absolute reference to a student who did) and compares it with the range F2:CY2 (that gives you a lot of questions to work with) then asks for an exact match – FALSE (weird I know but that’s excel’s thing). The code will then give you a count for how many cells in the range match the colour of the reference cell – in this case F2.
Normal 0 false false false EN-US JA X-NONE MicrosoftInternetExplorer4 
This is just the way to reference that colour count output and calculate the percentage. Easy.
We’ve had Promethean people here to our school to discuss the issues and some progress is being made to fix these basic problems but it is slow because we’re in Australia and the programmers are in the UK.
It is a clunky workaround for what should be a better/more user friendly output from ActivExpression but I hope you can get it to work.
We have lots of teachers using it now who have no idea how it works but they only really need the final number at the end of the day.
Cheers
Andrew