Add ROR return on risk (aka return on margin, return on capital).. normalize per trade first then avg of trades. Apply same normalization to PCR.
PCR calc add normalization, per trade, then avg trades. Current calc is sum P/L over sum credit received, so there is bias towards recency (if backtest is +EV) and premium (if backtest is fixed contract). Additionally the PCR calc cancels credit and debit received - this would be better served by only calculating for credit trades, this way in say a port with a credit selling and debit trade mix - the PCR calc would remain meaningful, alongside the ROR calc.