I'm an author of this report, so thought I'd offer some feedback.
First, the iOS applications that Veracode scans are written in Objective C (and probably some C or C++). And the Android apps are written in Java. (Yes, you can write iOS and Android apps using portability frameworks like PhoneGap; we separate those findings out into a separate category.) We used iOS and Android as shorthand so that (a) readers would more readily make the connection with what ObjectiveC meant, and (b) we could separate Java used in Android, which has a distinctive risk landscape, from Java used in other applications.
Second, we choose to report on application prevalence, or the number of applications showing at least one of the vulnerability, rather than number of vulnerability occurrences. The application prevalence metric is more meaningful when talking about the overall risk of a large number of applications. There is value in the vulnerability prevalence metric, when it comes to planning remediation effort, but for this study we focused on the former.
Third, we do report average flaw density metrics in the appendix of the study, along with a discussion of some of the limitations of this metric. I suggest reviewing the actual study (it's only about 20 pages) and then posting any additional questions.
Thanks for the questions and keep them coming.