Rounded up group footer sum doesn't match the sum in report summary

I am using a takeoff software for drywall estimating called planswift, and it feeds data into fast reports 5. I figured out how to sort and format the data just how I need it, the one problem I can't seem to figure out is why the sum in my report summary won't add up to the same amounts in my group footer. I know that it is adding all my quantities and then rounding at the end, but in my group footer I have the quantities summed up and then rounded per folder. Those quantities that are rounded up in the folder is what I need added together. I don't know how to write code, and the bit that I did try and teach myself didn't work.

The formula that I have in my footer is [Trunc((SUM(<EstData."Qty">, DetailData1, 1))+(0.99))]

Basically, as I measure prints on a new building, I label the area that I am taking off in a folder and fast reports will sum up my material for me so I know how much material to stock in that area. The Trunc(n)+(0.99) is what I used to round up my materials (except for materials that are already an exact count) but when I use this formula in the summary, it's always a little short because it's adding ALL the data instead of by folder still. My data is grouped by folder, then name of the material, then the description (for different sizes of drywall). I read somewhere that you need to have the data source be rounded up before it goes to fast reports, but in my case if I have my material rounded up before its added, I will have a lot of excess and I would be wasting money. There is a lot of individual counts that are less than one, and the bigger the project, the more excess I will have.

Is there a way to essentially declare the the formula in my group footer as it's own variable and use that in another function? Or save the list of rounded sums as an array and sum that up (and possibly multiply it by the cost of my material for a total price)? Or is there some simple setting that I am just missing to make my summary follow my grouping order?

If anyone can help that would be amazing. I am not familiar with code/scripts so if that's what I need then please try and explain it simply. I currently just feed my data into an excel spreadsheet manually and have a template with formulas that does this, but the process to fill out the spreadsheet is long and slow and I am trying to automate it.