IoTaWatt + Shell EM in Home Assistant?

About to get my IoTaWatt installed which will give me Grid, Solar and the major appliances (oven, spa, pool, A/C etc) into Home Assistant, but I’m wanting to get a finer breakdown of items that are on a single circuit (dryer, NAS, Computers etc). If I get a Shelly EM installed behind the GPO for these devices would that give me a reasonably accurate view? I assume I can subtract these from the IoTaWatt totals in Home Assistant?

If you need more than 14 circuits Weigh up the cost of a second iotawatt vs using Shelly devices.

In theory though, if you can get the data into the same bucket you can do the necessary maths. Has an overview of what is needed to get the Shelly data into influx db.