Confusing. I asked onlinetires.com about 124730, and this is what they answered:
"I called my Bridgestone representative and I gave them that part number you provided me with and they are telling me nothing is coming up under that item number # 124730.
I ask to see the Bridgestone have tire size build for a Porsche and they suggested this item part # 127730 below: Price for each is $284.77"
The tread matches the Scuderias, they are both RE050A, and the tire is Y rated. Why does the "N1" matter? Could be a typo on your invoice?
2,000 posts! That's a lot of billable hours.