I've found an Excel add-in called XLFit. I've changes the spreadsheet to include this and to tidy it up. You can copy the coefficients from HPTuners and paste onto the "Original Coeff" sheet. This will graph the VE table and show the table on the "Original VE" page. After logging the car you can then copy and paste the AFR % error from HPTuners into the "AFR % error" sheet, assuming the row and column titles are the same. The AFR % error data will adjust the VE table. The adjusted table is shown on the "New VE" sheet and the new coefficients and graph on the "New Coeff" sheet. You can then copy and paste the new coefficients back into HPTuners and then go and do some more logging.
The problem is that you can only use XLFit for 30 days before having to pay and it's not cheap. If you want to have a look it is here http://www.idbs.com/Decision/XLfit/ . Unfortunately the spreadsheet won't work properly without installing XLFit.
If you are going to play with the spreadsheet please note that it has not been tested in real world conditions so make sure the figures look sensible before using them.
Here is the Spreadsheet. http://users.bigpond.net.au/bcar4179/e38_e67 sd ve tuning afr.xls It is now around 1 MB