Dear Fellows,
I post some pictures of my metering system for solar Grid tie:
The meter has an interface and also measures:
1. Used power in kWh
2. Power sent back into the grid
3. Line voltage between L1 and L2
4. Measured current
5. Real time power involved
6. Power factor of L1 and Neutral
7. Power factor of L2 and Neutral
The display show these items with an interval of a few seconds.
They call this power (usage) meter 3- wire although I only had to feed the 2 phases through it. The metering works with 2 CT's mounted inside.
Installed are 2500 Watts panels and here are the readings:

Here it shows the line voltage.
And below the amperage:

10.8 Amperes on the display. When I measure L1 and L2 separately with a clamp meter (True RMS), I read about 5.2 and 5.4 - a small discrepancy but when I measure the current through the neutral, I find the difference of 0.2 ampere.
A strange situation occurs when I check the Power (in kW) real time.
The display gives me not what I expect. 
Has anyone experienced this before and what is you explanation behind it?
Thanks for your input. D.