sim800c current consomption high while power down

I use with aduino a SIM800c mini dev board.

I am trying to reduce as low as possible the current consomption between 2 sms (I send SMS every 2 hours).

When I send AT command : AT+CSCLK=2 or AT+CSCLK=1, current goes down up to 1 mA as described in documentation.

When I sen AT command : AT+POWD=0 or AT+POWD=1, sim800c power off (led off) but current consumption remain high : around 40mA. :o

This is very strange behaviour ! Any idea ?

Should i use pwrkey instead of at command ?

I don't see how this is an Arduino problem. You need to discuss this with the SIM800c people.