Hot Fox: [Access VBA Central] Problem with Report Totals

I have several fields in my detail section that are calculated from adding the values of a bunch of database fields together. The list of fields that are added changes from month to month. So, in January, bucket 1 is for January, but in February bucket 1 is for February, and so on and so forth. We then take those buckets and add the values for to obtain totals for a given year and year to date. We show the current year and 2 previous years data in the report, so I have 6 aggregate variables, 3 for the Years' grand totals, and 3 for the YTD totals.

Now, I need to take those year total and year to date fields and give a grand total for them at the bottom of the report, a seemingly simple task that has me going nuts. Here is the gist of my code.
Dim agg_Yr1_Grand, agg_Yr2_Grand, agg_Yr3_Grand As Double
Dim agg_Yr1_YTD, agg_Yr2_YTD, agg_Yr3_YTD As Double

Private Sub Detail_Print(Cancel As Integer, FormatCount As Integer)
agg_Yr1_Grand = agg_Yr1_Grand + Nz(Me.Ctl05)
Me.grand1 = agg_Yr1_Grand
agg_Yr1_YTD = agg_Yr1_YTD + Nz(Me.YTD2006)
Me.ytd1 = agg_Yr1_YTD

agg_Yr2_Grand = agg_Yr2_Grand + Nz(Me.Ctl06)
Me.grand2 = agg_Yr2_Grand
agg_Yr2_YTD = agg_Yr2_YTD + Nz(Me.YTD2007)
Me.ytd2 = agg_Yr2_YTD

agg_Yr3_Grand = agg_Yr3_Grand + Nz(Me.Ctl08)
Me.grand3 = agg_Yr3_Grand
agg_Yr3_YTD = agg_Yr3_YTD + Nz(Me.YTD2008)
Me.ytd3 = agg_Yr3_YTD
End Sub

Private Sub Report_Open(Cancel As Integer)
agg_Yr1_Grand = 0
agg_Yr2_Grand = 0
agg_Yr3_Grand = 0

agg_Yr1_YTD = 0
agg_Yr2_YTD = 0
agg_Yr3_YTD = 0
End Sub

Everything works beautifully if I do a Print Preview, but as soon as I hit print, the totals are all out of whack. Mysteriously the totals add in extra dollars. If I sit there and click the Landscape button over and over, you can watch the totals go up and up and up and up without bound.

I've tried this in both Access 2000 and 2007, with the same result. I've tried Compacting and Repairing, with no effect. Any ideas?