Do the italics appear in the hard copy of the Amplified? (I lent my hard copy out a while back and haven't gotten it back), in either case you would have to ask The Lockman Foundation, since they did the translation and/or American Bible Sales, since they created/distributed the module and can best explain the whys and wherefores of the contents.
Not all translations follow the same conventions (like putting variants in italics), that is why it is necessary to check the introduction section to see what conventions they do follow.
I learned some time ago that no translation is perfect, and therefore, by extension, no edition of any translation is perfect.
That being said, I agree that the Amplified is a useful translation because of the way it helps nuance the text.
Thus says the LORD, "Let not a wise man boast of his wisdom, and let not the mighty man boast of his might, let not a rich man boast of his riches; but let him who boasts boast of this, that he understands and knows Me, (Jeremiah 9:23-24a)
"Defenders of the faith are inclined to be bitter until they learn to walk in the light of the Lord. When you have learned to walk in the light of the Lord, bitterness and contention are impossible." --Oswald Chambers, in Biblical Psychology from The Quotable Oswald Chambers.
