It seems that it is disabled for me. I am using Redmi S2 (MIUI 10.3.1.0) along with BetterBatteryStats. I can only see Doze Interactive Time in the BBS log. I have been using BBS for almost 10 months and I never saw Doze Idle Time in the log. I went through data wipes and full internal storage wipes during this period but still I didn't find any change in the logs. So is doze even enabled in MIUI? If so, is it working for you?