Concerning fat emboli

From correspondence with Paley:
1. "Is the 4% FES and 1% DVT rate for bilateral femoral lengthening only, or for all procedures?" --- For all surgeries, from an assistant
2. Paley has done >10k procedures

From correspondence with Donghoon:
1. "Dr. Donghoon Lee has done about 7000 cases over 10 years and has 0% of major permanent complication rate because of his professional surgical technique and the after-care"
2. "So far at DALRI, we do not have any incidents with any deep vein thrombosis and fat embolism"
From an assistant

Wait, so both have cases in the thousands, but Paley's FES is 4% vs Donghoon's 0%? DVT 1% vs 0%? I think Donghoon does way more LON tibias, but has had precice stryde done multiple times as well. How does FES of 0% make any sense?