Isn't the difference simply a matter of conversion, from one system to another? Does it really matter?
If you're scheduling an appointment with one of Satan's followers, it probably doesn't matter.
But, it is NOT simply a conversion (as in from Fahrenheit to Centigrade or inches to centimeters). The two time systems are DIFFERENT and based on different principals.
Yahweh's time is natural, it uses His nature to control it. Satan's is completely artificial and based solely on calculation. Yahweh's time harmonizes with nature, Satan's ignores it. Yahweh's time synchronizes with His set aside Holy Days and Sabbaths. Yahweh's time is coordinated with His harvests on earth, which are types of, and point toward, His eventual harvest of souls. (see HARVESTS OF REDEMPTION)
If Satan can get people to follow his time and forget Yahweh's nature, time, Holy Days, Sabbaths and harvests, he can get them to forget Yahweh. More importantly, they will be following (obeying) him and not Yahweh. That is Satan's goal.