The problem is that not all SCT013’s are alike. The SCT013-000 (100A:50mA) is the only true current transformer. That is to say that it generates a current that is proportional to the primary current on the wire it is clamped around.
The other SCT013’s - 050, 030, 005 etc. are actually voltage transformers. They have an internal burden resistor that causes them to produce a voltage that is proportional to the primary current.
IoTaWatt has an internal burden resistor on each input channel that combines with the external burden and skews the reading. If the 150W and 100W are the numbers you are seeing, you would have 20 Ohm burden resistors in the IoTaWatt. The SCT013-050 has 37.2 Ohm resistors. So combining those two you get an effective 13 Ohms.
I would recommend you get rid of these voltage type CTs and either get some more ECS1050s or some genuine SCT013-000. But if you are adamant about using the 050s then you can kludge it as follows:
In the IoTaWatt setup, change the value of the burden resistor for that channel to 13. Then reconfigure the CT as “generic” with turns = 1860 and shift of about 3.
While this works OK, it only provides about 1/3 of the resolution that you would get from an ECS1050 over a 50A range. That’s significant when you are measuring 150W. 1.25A (150W @ 120V) is less than 1% of the range when configured this way. With an ECS1050 it’s 2.5% of the range. I guess I’m trying to say don’t expect a perfect match with the ECS1050. You’ll be in the ballpark.
You should see the wattage return to close to 150.