Yes, I was very detailed in my description of the type of visa my parents need. I even tried calling four times, on different occasions, just to speak to different representatives- and ultimately, a supervisor - because I did not believe what they were all telling me. They said that as long as I had received an email stating that my case is now at the embassy in Manila, I could go ahead and schedule the appointment.
So, against everything I understood and believed, I tried to schedule an immigrant visa appointment through the USTravelDocs website. And it went through. The system asks you to choose the type of visa, and there is an option for IR-5.