pendragonman
Absent Friends Margrave
Hans and Don went over this several times a few months ago. The outcome of that was Don and Marc agreed the negative efficiency didn't turn the whole RU calculation to a negative number.
The official result of a negative efficiency is the multiplier is now a fraction. Specifically: -1 eff = multiplier of 0.9, -2 eff = 0.8, -3 eff = 0.7, -4 eff = 0.6, -5 eff = 0.5. These are the values used for the Trade Map data calculation of the RUs as shown in the wiki.
This is official errata from DonM and Marc.
This is crazy. How do we keep up with this whacky mathematics without a scorecard?