using Drupal 6.2. views-calc 2009 seems to be the latest for drupal 6

I'm finding a significant problem I cannot resolve. views-calc seems to hang on to old values that no longer exist in the database.

I have a test set up with 8 entries and the calculation of totals of 8 rows of integers for 3 columns. Payment, GST and donations.

Total for Payment is about 1200 yet views calc SUM Total shows 14,760 GST has 8 rows not exceeding 22.27 in each row yet SUM total shows 2945.35998535156 GST has 6 entries largest is 120 smallest is 10 SUM shows 3000

Display Calculation is set to SUM.

GST calculation is: $node_field[0]['value'] = $node->field_payment_total[0]['value'] - ( $node->field_payment_total[0]['value']/ 1.1);

I find that if I edit a registration entry then the edited amount is added to the total shown by views-calc it does not replace the old non existent value.

If I start afresh with new content type and the same computed field under a different name views-calc produces correct values but editing even one value in the saved table destroys the calculation.

It seems that there has to be a way of clearing the amounts stored by views-calc but I cannot find the storage field in the mysql database.

I've repeatedly flushed caches and refreshed the screens.

Is there a way of clearing extraneous values? Where and why are they held by views-calc?

I can easily do the calculations in the mysql database tables and results are correct, views-calc is not.

Help is much appreciated thanks Roger