Rounding Issues |
  
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Rounding Issues |
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To prevent the prices, results of multiplications, from having many decimals, it is desirable to round them.
The law imposes that, in the final report, the total selling price:
1.have two decimals
2.be exactly the product of the quantity into the visible unit selling price.
These constraints may be conflicting.
Do not confuse:
▪The last significant decimal (rounding, reserved to selling prices)
▪The count of displayed decimals, controlled by the menu Home>Edit>Format Cells>Number; if needed, QDV7 stuffs with zero(s).
Say the calculated selling price is 3.14. The displayed values depends on the settings:
Decimals \ Rounding |
1/10 |
1/100 |
1 |
3.1 |
3.1 |
2 |
3.10 |
3.14 |
3 |
3.100 |
3.140 |
QDV7 calculates in the full precision, and displays the values at user's will on the estimate.
Notwithstanding the full precision in costs, a deviation may occur due to rounding
▪in the sub-total between header and details of a group in the Minutes view
▪in the grand total between WBS and Overhead workbook.
Description |
Qty |
Cost per Unit |
Total Cost |
A |
1.77777 |
12.98 |
23.08 |
B |
1.45 |
14.99 |
21.74 |
after collapsing group (F10) |
|||
A |
1.77777 |
25.21 |
44.81 |
The group's total cost is not the sum of the components' total costs.
NOTES
- The task sub-total uses the group's total cost
- The Cost per Unit is computed from the group total cost.
ROUNDING ONLY ON THE GRAND TOTAL
Without rounding, the constraint 2 is NOT fulfilled: the column 6 is not the product of columns 1 and 5
1 |
2 |
3 |
4 |
5 |
6 |
|
7 |
8 |
Quantity |
Used unit cost |
Visible unit cost |
Factor |
Unit selling price |
Total price |
|
Rounded Unit selling price |
Rounded Total price |
1031.12 |
12.2335 |
12.23 |
1.1455 |
14.01 |
14,449.57 |
|
14.01 |
14,445.99 |
1001.12 |
17.5566 |
17.56 |
1.1455 |
20.11 |
20,133.61 |
|
20.11 |
20,132.52 |
2064 |
40.4555 |
40.46 |
1.1455 |
46.34 |
95,649.42 |
|
46.34 |
95,645.76 |
Grand total |
|
|
|
|
130,232.61 |
|
|
130,224.27 |
With rounding, the constraint 2 is fulfilled, but the grand total in the WBS may differ from the objective set in the Overhead workbook to produce a fixed margin.
There are two ways to offset the deviation:
▪Adding a row at the end of the WBS bottom zone (refer to Bottom Area) where the bidder forcefully grants a discount to match the Overhead workbook
▪Using the trick Target; this is the only way in public contracts.
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