Someone said when IV decreases, Theta will be higher, especially when it is approaching expiration, vice versa. On the other hand, I tried to punch in some numbers in the simulator. The result is just the opposite. Also, I had been seeing theta chart supporting my observation. The chart (Theta vs IV) looks odd if I think IV as how many days left. The lower IV is essentially same as less days to expiration(correct me if I am wrong), and obviously theta will be higher close to expiration in chart (Theta vs time). I can't find the common ground on those two charts.