Adding to A Short Soybean Calendar Spread

We will be adding to our short Soybean position by selling the (H20-K20) calendar spread. This spread is sitting on the channel created by the 5-yr and 15-yr patterns. It has profited 13 of the last 15 years when sold on 9/12 and bought on 10/2. This trade has an average profit to draw-down ratio of over 200% while the average best is easily 5x the average worst. On Thursday, I will be selling the Soybean (H20-K20) calendar spread at or near the current price with a limit of ($12.75).