I notice that ERNiCrFe-7 has 5%max Mn. Mn was one of the elements added to NiCrFe-3 (182) to improve all posiiton crack resistance over the old NiCrFe-1(132).
It also appears as though one of the primary alloying elements is Nb. Which means that it should respond under welding regimes similar to 625 (although 7 has less than the Mo-3). Just looking at it what is working against you for hot cracking is Al, Cu, and Nb. Mn may be working for you.
I sure would love to get my hands on some really good metallurgical info on this alloy (i wonder if Dick has anything specific on this alloy).
The A version specs out Co, Zr, and B. While reducing the Cu content and the Mn considerably. Would this be hot crack adjustments? The Al has been increased.
I know I'm describing the water here, but it may raise pertinent questions.