after some months, here's what I learn from DSP-W215
a. No scheduled time set, you manually press turn-ON the physical button via W215 itself, power-failure simulation and then re-applied back power,  it will NOT remember last state, it remains OFF throughout till the next schedule.
b. E.g. A scheduled time was set that it is ON between 2PM to 5PM.  Power failure happens between 2pm-5pm and power restored before 5pm.  The w215 will set it to ON after few minutes.   So I am happy on this
Summary: Power Failure scenario will work if there is a Scheduled Set on that time frame   (firmware 2.2 and mydlink home v3.07 (ios)