GA3 performs its calculations on an invoice line level and not on the overall invoice totals.

We chose this method as almost every accounting package on the market also uses this method, such as Sage Line of products, Quickbooks and more.

The main difference is noticeable if you are comparing the VAT calculation by performing the following Sub-Total X 1.175

This may not always add up to the VAT total shown in GA3 due to rounding. However GA3 is correct.

An example of this would be :

 
Line 1 - qty 1 X 35.00 + vat

Line 2 - qty 1 X 45.00 + vat

Sub Total = 80.00

VAT = 14.01

Total Due = 94.01

 
You would assume that 80.00 + vat gives a total of £94.00 but due to them being listed as separate items, the vat per item is calculated then rounded and then added together, this gives the same results as if you where to invoice each line as a single invoice.

The following will explain as simple as possible as to why this is the case... Lets take a closer look...

Line 1 : 35.00 + vat

Vat : 6.125 (rounded = 6.13)

Total : 41.125 (rounded = 41.13)

Line 2 : 45.00 + vat

Vat : 7.875 (rounded = 7.88)

Total : 52.875 (rounded = 52.88)

Therefore the totals are :

Sub Total : 35.00 + 45.00 = 85.00

Vat : 6.13 + 7.88 = 14.01

Total = 41.13 + 52.88 = 94.01

Below is a Screenshot from Sage Instant Accounts 12 As you can see, the total is also 94.01 as it is within GA3 and the VAT figure is 14.01

Hopefully this will help you to understand how the calculations work in GA3 and how they are indeed accurate for the type of invoicing being performed.