Step one: reconstruct the record
Scoring starts from the account's own fill history rather than a displayed PnL figure. Fills are grouped into positions, positions into closed trades, and closed trades into a realized PnL series with timestamps. Unrealised PnL is deliberately excluded: an open position is a claim, not a result.
This reconstruction is also where records get rejected. Too few closed trades, too short a history, or a series dominated by a handful of outsized outcomes cannot support a score, no matter how large the headline number is.