Can you please confirm you are familiar with the concepts explained in the article I shared?
D-Leverage, Darwinex Position, etc.? Also, just multiplying the final return * 15 like you did is a rather vague approach IMHO.
If I may, I would recommend checking the trader's trading journal, his Rs chart to see how his risk evolved over time, etc.
Also, it could well be that losing positions were less amplified than winning ones (DARWIN's profit is 20 times higher than its US's, whereas the DD is "only" 14 times higher...
All in all, there are several aspects that may affect how an US is replicated by its DARWIN other than "just" comparing its US' return with its US's return * 15.