I am currently using Trello to manage custom CAD/CAM manufacturing orders. I've been able to dramatically reduce the amount of manual entry for cases using butler and some other 3rd party automation software. One thing I'm still struggling with is setting staged due dates, so I thought I'd ask you guys. The best way I've come up with to see our staged due dates is having custom fields for each one and then setting the Card due date to the next custom date as it gets moved along the lists. We start with the "ship to customer" date, subtract 2 working days for the "finishing" date, subtract another 2 for "Manufacturing" date, and yet another 2 for "CAD Design" date. I would like to set 1 of those dates and have butler extrapolate the others. I found how to set the card due date based on a custom date field +- working days, but not the option to set custom field date based off another date +- days. In the butler documentation it shows some potential solution by directly coding the butler rule with arithmetic expressions but I can't find anywhere that those expressions can be manually entered. Thank you for any help! Sorry if this has been answered, I promise I looked haha!