Reproducing RowStates with Rest API

We’ve got Epicor 10.2 on it’s way soon to replace our 10.0 so I’ve been working through some automation we have to take it away from directly linking to dlls and using the Rest API instead.

I’ve succeeded with most of it but there are a couple of OrderAlloc calls I’m struggling with. The one that I’ve spent most of my time with is ‘api/v1/Erp.BO.OrderAllocSvc/Recalculate’ (Unreserve is another one but I’ve not spent enough time on it to rule out obvious mistakes yet).

The problem seems to be, and I’ll be gladly corrected, is that in the dll / DataSet world, to get a row to be recalculated using this object/method you seem to need to set the RowState of the DataRow to Modified. Setting RowMod or changing any other value in the table to match the trace seems to do nothing, the key seems to be getting the row into this section in the trace:

The problem I have is that I don’t know how to replicate this in the RestAPI json. Is anybody able to shed any light or point at the right solution if I’ve misunderstood what’s happening?