How does Zervant calculate?

There are two ways of calculating totals when it comes to invoicing. 
Method 1: the sum of rounded values
Method 2: the sum of values, rounded
 
Zervant uses the Method 1. See below: 
 
 
 
Method 1: Sum of rounded lines
For example, the sum of each line is 5.764, which is then rounded to 5.76 (2 d.p.). As such, the total of the invoice using method 1 is: 
5.76 + 5.76 = 11.52
 
 
(Method 2: Sum of lines, rounded  
5.764 + 5.764 = 11.528 
Rounded to 11.53)