'the grade may be much lower at the start of the course until more assignments are complete'
I don't think that's the case Chris - I think the assignments are only taken into account in the weighted average (which I believe is how the Course Total is calculated - by default anyway) when they are graded, so having assignments that have not been submitted yet, or even submitted and not graded, wouldn't actually alter the course total until such time as they are graded and the score becomes part of the course total calculation. But that would also be because I am showing the percentage rather than the total score as in the simple added sum of the grades achieved, so that's the total achieved out of the total possible, and the total possible is only calculated from the graded assignments. I think what you say would be the case if the course grade showing was the straight total of grades.
I do like the collapse button you've used, but I also like the idea of having the total there and turning it into a clickable link to go direct to the full user grade report anyway. I guess you could even do both and treat the total I had put as the clickable button to make the full report appear on the course page.
One thing I've noted - the css I put in needs to be added to for the options for other columns which are hidden by default in the gradebook setup settings. I only looked at the ones that were already there by default, but the others need to be hidden too.
What I'd really like to do is get to the bottom of the calculation so I can pass a variable rather than the whole report and then use a graphical representation of it, rather than just the number. To put that alongside a similar graphical representation (in the header) of the progress bar to track how far through the course the students are - Progress & Grade - would, I think, be quite a powerful tool
Something else to add to my to-do list )
R
Attached a txt file - has the required php to be included in a layout file (the coursegrade is now a 'button' to link to the full user grade report), as well as the css definitions (I think I've turned everything on so I can hide it in the css, but if anyone knows different please feel free to post here). Copy and paste the required bits to the relevant files (or create new files for them and add them to your theme appropriately.)