My non-precision approach model had been one or more IAFs and then a common core...

My non-precision approach model had been one or more IAFs and then a common core approach from the IF.  In fact, there can be one or more initial approach routes from the IAFs to the IF, then the core approach.  Replace the IAFs with initial approach routes.  NOTE it is assumed in the code that there is a unique IAF per initial approach route.