It is important to understand how a Negative takeoff object affects Condition totals. Setting a takeoff object (or objects) as "Negative" is not the same as deleting an object.
Example
If you draw 10 of the same Count takeoff objects on your plan, and then set one of them to negative, the cumulative result is "8" objects.
The object(s) set to "Negative" does not first increase the total and then reduce it, that negative takeoff object only reduces the cumulative quantity. So in the above screen shot, there are nine (9) Positive objects and one (1) Negative object (9-1=8). Effectively, the one negative object cancels out one of the positive objects.
If you simply want to reduce your takeoff count by "1", delete one of the takeoff objects you've drawn.
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Drawing Attachments