I finally tracked down the interstitial bug and pushed a fix.
I have also extended the createAdView method to accept x and y offsets as well as a scale. The x and y offsets are from the top left corner of where you originally place the banner (ie. TOP + yOffset, CENTER + xOffset). Scale will grow the banner while maintaining the aspect ratio to keep the ad looking good (ie width and height get scaled by the same amount).
[lua]
createAdView(verticalAlignment, horizontalAlignment, xOffeset, yOffset, scale)
[\lua]
The offsets and scale are optional and if they are not provided the defaults are 0,0,1 so this change should not break existing code.