android lvl check if purchased app is in the refund period

I am using LVL 开发者_开发问答to add licensing to my app. I was wondering if i can check if the person that purchased the app is still able to get a refund (is using the app within 15 minutes of the purchase). Anyone got some examples or directions he can give me for this sort of thing?

Or maybe an alternative: to check when the app was installed on the phone. i found this link -> installTime

But something was unclear:

the app source directory is never modified after install?

What about after update?

also found this comment in the licensing/ServerManagedPolicy.java:

 * These values will vary based on the the way the application is configured in
 * the Android Market publishing console, such as whether the application is
 * marked as free or is within its refund period, as well as how often an...

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Just set the DateTime in the app and save it as a Preference when you start the app. Then evaluate it at some point to find out if 15 minutes has passed.