Yes, it looks like the guard connection makes the difference. If you can find tweezers with a guard lead, you should be able to calibrate your meter too.
With the tweezers closed, the meter on Rs 1 KHz selection, reads 0.007 Ohm and 0.12 Ohm on DCR.
I can't remember where I read this, but apparently the impedance should be more than 9.5MOhm in 'Open' mode and less than 1.1Ohm in the 'Short' mode, for a successful calibration.
Also, like I mentioned in the other thread, APO (Auto Power Off) works fine. The soft button has to be tapped rapidly to make the selection. There is no feedback beep on selection.