iPhone changed under warranty-Maximum allowed devices for apps

Hello,

I had purchased an iPhone 4s from an Apple Store in November 2011 and had it changed under warranty after 2 days, because it has a weird noise on vibrator.

Now, I'm having this week again replaced my iPhone 4s due to a dark area on screen, because of a piece of dust which remained on camera's lens. The service engineer from Apple told me that the lens cannot be cleaned, so my phone will be replaced again in warranty.

There is that policy from Apple which says that the apps purchases can be used in maximum 5 devices. Basically, the apps purchased within last months have been passed through 3 different iPhones replaced under warranty. Theoretically, I have 2 devices left to install my apps.

Does Apple counts this and sees only one device, or this number decreases on every iPhone replaced under warranty? How is it in practice?

Thank you,

Andrei