Using a splitter for mains?

Hi, I have split 400 amp service - so I have 2x200 amp panels located in different parts of the house.
So I got one IoTaWatt for each panel, as well as (220 amp) CTs for the mains and assorted CTs for essentially all of the branch circuits.

Right now for both panels I have one 200 amp CT on each leg of the main, with each CT connected to its own input - inputs 1 and 2. For some of the smaller branch circuits I combined CTs with splitters, and for some I was able to run 2 or 3 through a single CT - never exceeding the sum of the rating of the CT and being mindful of the phase. Everything more or less adds up (dwells ± 20 watts from 0) when I sum the branch circuits and subtract the mains - so I believe everything is working as it should.

My question is whether I can use a splitter for the existing mains and have them share an input, freeing up another input. I wasn’t 100% clear on how this applies:

Two individual CTs can also be combined with a common headphone splitter and fed into a single IotaWatt input. When combining this way, both CTs must be the same model with an individual capacity sufficient to measure the combined capacity of the two circuit breakers.

Does this mean I would need 400amp CTs to do this instead of the 200 amp ones I have now? Thanks in advance.

It does mean you need 400A CTs, but in reality you don’t need to meet the combined capacity, only the combined real load. Since you have the CTs going into individual inputs now, you can look at the history to see what kind of Amps you are using. Be careful because Graph+ is reporting average amps for each interval. Where you see peaks, zoom in to see the 5 second values. If you are comfortable that the total doesn’t exceed 200A, give it a try with the 200’s.