Incorrect. This new line appears if the IAP mechanism is present in the app. Regardless of whether anyone has used it. It's only the Top bit that requires a purchase.
No. It's correct what I said. I just checked it once more: There is a new game "Fantasy Grind" (just as an example, I didn't buy it). It costs €0.89 and has In-App Purchases.
Here is the link of the app for the Austrian App Store (no IAPs visible right now, proof enough?):
https://itunes.apple.com/at/app/id587585947?mt=8
(The proof only works until somebody buys any IAP of the game in Austria.) I can see the IAPs only when I go to (without "at"—my country code—in the url) the "international" iTunes web page (the little table):
https://itunes.apple.com/app/id587585947?mt=8
Only that way I can see the IAPs (table, no line) in the iTunes
web page. But I can't see them in the iTunes
APP (iOS App Store) on my Mac (and the App Store app on my iOS devices)! And I can't see them via the regular app url for my country.
No line and no table because nobody bought any IAPs of that app in my country.
I added screenshots as proof—I made them a few minutes ago. The first one is the international web page (non-standard for my country). The second one is the iTunes
app on my rMBP with OS X 10.8.3: No hint to IAPs at all!
Compare: Here you can see the new line (when somebody bought any IAPs) in German-language iTunes App Store:
https://forums.macrumors.com/threads/1560022/
Please ask if anything is not clear. This problem is really evident and annoying esp. in small countries. Since years (exactly since IAPs are present)! It may last weeks or months until somebody buys IAPs of an app. Nothing changed with the new line. And there are even smaller countries than Austria with iOS App Stores…
It's valid for ALL countries: IAPs will show up only if at least one user in the country has bought them. And when the user bought only ONE IAP—only ONE line will show up in the little table even if the app offers more than one IAP.