On my system, and all of our users, whenever the user clicks on the report (anywhere on the report) it switches the zoom level up and down. In the detail band, a function is called which increments based on the value in the current record. Zooming in/out on our systems in both 8 and 8 call the function over and over and the total is incremented by the values display on the current page. For instance, if there are 5 records that are displayed on page one in preview mode like:

The programs which call this frx all set totcomcash to 0 before anything else is done at the top of the prg.

For example, if type 1 = cash, type 2 = chk, type 3 = checkforward

record     type   commission    amount
recno()   re_type   camt       namount
1           1       50.00      1000.00
2           1       10.00       800.00
3           2       10.00       900.00
4           1       50.00      1000.00
5           3       10.00       800.00

in the detail band at the far left of the detail line there is a field whose expression is
chkcomm('XMITTAL'). In the chkcomm function something similar to the following occurs:

FUNCTION chkcomm
lparameters xreport

IF re_type = '1'
   totcomcash = totcomcash + camt
ENDIF
RETURN

In the summary band, totcomcash should equal 110.00 based on the 5 line items above. It does equal the correct value if I only preview and switch pages but do not zoom in and out on the detail page before I move to the summary band on the last page. But if I zoom in and out on page1 and then jump to the summary band on page2, the value of totcomcash each time I do it will double i.e., 110.00, 220.00, 330.00, ...

I can duplicate this in both VFP8 and VFP9