Ron:
Yes, I'm surprised. But then, I'm not aware of the limits and "gotcha's" in your approach, either.
A good algorithm designer (subsystem engineer) will also have a very big bag of mathematical and instruction shortcuts that approximate the DSP funtion they are implementing, with reasonable and acceptable losses. Which makes performing more with less very possible.
I still think building and demonstrating an AM BCB receiver is a good challenge. It's very do-able without needing too many shortcuts, and the end product would make a fun project.
Best Regards,
Brian - K6BRN