SIM900 module and Power consumption

I'm using a module like the following SIM900A module

The module is turned off when the report(SMS) is sent by using the LM2596 disable pin and my pro mini goes in Sleep mode in order to save power.
I noticed that somehow the cirquit consumes 10~12 mA more than expected even when my arduino is in sleep mode AND the module is totaly out of power-supply.

After some tests i realized that the 10mA consumed in the TX line that connects my arduinos D7 pin and the SIM900 module.
D7 is used as TX and
D8 as RX in SoftwareSerial virtual port.

There is any idea why this consumption takes place ?
Any idea how can i bypass-solve this problem ?

Thank you in advance.

Any idea how can i bypass-solve this problem ?

If the SoftwareSerial class doesn't have an end() method, see how HardwareSerial does it, and add one. Then call it, and then turn off the pin (if end() doesn't do that).

Thank you Paul for your reply

During last nights test i realized that ..
by simply powering off the pins those 10 mAmps saved.

digitalWrite(8,LOW); is working fine !

During my tests seems that when the module-arduino waking up from sleep the SoftwareSerial working fine without any problem.

Do you think that this will cause other additional problems ?