but in my last shared DE cycle, we received 5 eggs. By day 3, we only had 3 still dividing, and only one that looked good. By day 5, we still had 3, but only one that was where it should be. Transferred two and third one didn't make it to freeze. I am pregnant with a singleton. So, my stats were pretty similar and it worked.
With my OE cycles, I never had 8 cell embryos on day 3. I did not have success, but my obsessive inquiries with Dr. Google found tons and tons of positive stories with 6-7 cell embryos.
I wonder what time your friend's ER/ET were. If the ER was late in the day and the ET was very early, it is possible that they didn't have the full amount of time to make it to 8 cells.