emonTx Arduino Shield- ISP Header?

Hi, I received my emonTx Arduino Shield and built it last night. I am fitting it to an Arduino Mega 2560.

I am a bit confused by the fit between the emonTX shield and the Arduino- the pins on the bottom of the CT sockets are touching the metal case of the USB connector, and the boards do not sit parallel.

If I set the boards parallel, and leave space between the CT socket pins and the USB connector, the 6 pin ISP (ICSP?) header (female) is not connected.

Is the ISP (ICSP on the shield's screen print) header used? If not, I don't have to worry, and I can mount the boards so that the CT socket pins are not being shorted on the USB connector case.

Thanks for any info.