Why am I getting huge values of e.g. 94080 A for my currents on my Elster A1140? This doesn't look accurate.

With the Elster A1140, it returns the actual currents, in other words it has already multiplied it with the CT ratio. This is if you do Primary Metering, in other words: the correct CT is programmed into the meter.
If you have CTs but you have not programmed the CT ratio into the meter (secondary metering); that means an external meter multiplier has to be added to get the real value.
I see that in your Meter Details screen, you've got a CT ratio of 1600 / 5, which means that the multiplier is 320 in case of secondary metering. Your Primary Metering check box is switched off.
So, what Plug and Play Scada assumes, is that your meter is programmed at 1/1. It then assumes your meter has no CT programmed into it (that its CT ratio in the meter is therefore 5/5 or 1/1); and therefore it multiplies the current coming out of the meter with 320.
Unfortunately, you DO HAVE a CT ratio programmed into your meter, although it is wrong, with the result that your meter returns a current of e.g. 300 A, which we then multiply with 320, and then we log it as 96000 A.
The reason you switched off the Primary Metering checkbox is probably because you have a Pulse Multiplier of 2/1 (x2); because you have the wrong CT programmed into your meter.
For Plug and Play Scada to show the correct values in the Phasor Graph, you should program the correct CT into the meter, switch on the Primary Metering checkbox, and change the Pulse Ratio back to 1/1. Alternatively, you should program a CT ratio of 1/1 into the meter, and change your Pulse Multiplier to 640/1.