Admob plugin. Interval option not working?

I’ve just started looking at the Admob plugin for iOS and Android.

Even though I specify ads.show(“banner”, {interval=30}) the banner never cycles. 

It does cycle if I call ads.hide(), wait for a while, and then call ads.show(“banner”, {interval=30}) again.

The issue is the same for both iOS and Android.

Anybody else see this issue?

Corona SDK 2014.2197 Pro

Xcode 5.1

OSX 10.9.2

iPad mini iOS 7.1

Nexus 7 Android 4.4.2

Although I don’t think this is a reason for the issue, I noticed this in the log of my iPad:

<Warning>: <Google:HTML> Google Mobile Ads SDK: You are currently using 6.4.1 of the SDK. A new version, 6.8.0, is available at http://goo.gl/Zc0BYt . Please consider updating your SDK to get the latest features and bug fixes

Although I don’t think this is a reason for the issue, I noticed this in the log of my iPad:

<Warning>: <Google:HTML> Google Mobile Ads SDK: You are currently using 6.4.1 of the SDK. A new version, 6.8.0, is available at http://goo.gl/Zc0BYt . Please consider updating your SDK to get the latest features and bug fixes