Normally, when the order has been placed, the price should stay that way. Any other change on that item should not effect in any order that has already been placed. Only new buyer got that price.

But when my customer placed an order for Item A for $5. Later, I changed my discount and the value of that item increase to $6. It appear that Item A in the order that already been placed was also changed to $6.

Is this normal?

Thank you,