Wrong, a friend is currently going through this situation. I also assumed that the building application would be necessary for the KfW application, but the energy certificate alone is sufficient for the KfW 70 application. And it must be submitted by 31.03.
You are confusing two things here in my opinion.
Funding can still be applied for KfW 70 until 31.03.2016; that is the well-known 50,000 EUR. BUT .... the building application is always based on the applicable Energy Saving Ordinance. So if the building application was not submitted in 2015, the tightened Energy Saving Ordinance applies ... also for your friend. However, since the currently applicable Energy Saving Ordinance is, mathematically, just below the values for an old KfW 70, your friend does not lose out. The application for funding must again be submitted to KfW by 31.03.16 at the latest!
Rhenish greetings on the go