Please elaborate on what " and then zero's everything out on others" means. Are the line items 0 or the summary feilds? Are you using a summary calculation or a simple Sum field.
If teh the items are zeroing the test those fields on anoth layout with a list view and find why some are zero and some are not.
Be sure to not use the Running Total option in the Summary field if you are doing sub summary on reports, as it will automatically do it for you.
if you run a sub summary report of 6 items ( the same ), any related trailing sub summary totals will be based on the last ( 6th ) record ( not the first )
so if that last record has a blank match field, the totals may be missing
> For some reason, the report works perfectly for some orders, and then zero's everything out on others.
Let me ask this. What would cause a summery field to be incorrect? Maybe if I start there and work backwards I can figure out what is happening.
Create a plain list layout showing the totals you need, the "key" fields, and any related values, then browse thru the records and look for anything odd
> What would cause a summery field to be incorrect?