Whenever comparing ads, make sure the impressions (or % served) numbers are very similar, otherwise they might not match up in time and thus could have different underlying causes for their different performances. For instance, an ad that runs for January might perform differently from one that runs in July due to seasonal demand. Even partially overlapping isn’t sufficient, you need to look at periods that both ads run for the same entire period. For instance, you shouldn’t compare performance of an ad for January and February with another for only February as the January performance of the first ad could change for other reasons and skew the two-month results.

I think you are correct in assuming the Google was simply offering one of the ads far more frequently than the other. What if you assume that and then correct for it? You should then be able to derive the original landing page data you were seeking.