do not enter the system off mode in hrs

I'm using [nRF52_SDK_0.9.2] and original module. As a tool, I use the keil.

"NRF_POWER-> SYSTEMOFF = 1;" in the SDK example hrs also written, does not enter the system off mode (current value does not decrease).Written location is "main.c". and I add it after; "conn_params_init ()".

By the way, when you insert it into the "blinky" enter the system off mode (down the current value)

Why not enter the system off mode "hrs"?

Thanks, uba