Round problem Sales Line

So Hi everyone, I've created a page where I use a list of sales order. Here the source table of my page is "Sales Line" and when i enter the same item twice (or more times) the round of the price in the column "Amount Including VAT" is not right, shpuld be always the same value but for each line have differences.

Here's the image below.



I try to comment this code in Sales Line table

Amount Including VAT - OnValidate()
GetPurchHeader;
"Amount Including VAT" := ROUND("Amount Including VAT",Currency."Amount Rounding Precision");

But everything stay the same... any idea?