The flyover text on Exotica's Influence reads: "Improves your base's production by 1% plus an additional 1% for each day you have controlled Exotica, up to a maximum of 10%":
Should read something like:
"Improves your base's production by 1% plus an additional 1% for each 4 hours that you have controlled Exotica, up to a maximum of 10%"
... based on the September 2012 update: viewtopic.php?f=2&t=29191 and observation.
Also not sure about the maximum of 10% or the exactness of the 1% for each 4 hours. Seemed to have gotten 10% in less than the 36 hrs that might have been necessary for that.