60 to 80% is nowhere close to what you need to acquire language as a beginner. Try 90% and up -- 100% being optimal.
The answer is, there are few places you can get this sort of input. A good CI-based tutor or teacher will do it, but they are difficult to find in Taiwan, where people tend to teach traditionally. Podcasts are not really highly comprehensible for the most part.
This is the common problem with most of the "less commonly taught languages" and CI approaches -- there's not much out there. We're making materials as fast as we can but the other problem with that is the lack of a broad market. It takes a lot of time and money to produce good materials, and if there's no return or very little return, there's not much incentive to do a really polished product that's usable by someone else, as opposed to scribbling some notes in the margin to use next year when you teach the same thing again.
Maryknoll was sort of interested in this approach in the past for Taiwanese -- it would have been nice, but it never went anywhere. I doubt you could get Shi-Da to even think about it for Mandarin.