Robby, I see your point but I think, given that the Project/Flow Info is responsible not so much for the recording of contributions by artists but for the function of inserting this information into the score, the Arranger field is sufficient for this task if noted properly, e.g., “orchestrated by Robby Poole,” unless an arranger and orchestrator are involved simultaneously (in which case, you’d be better off entering this text freehand in the frame anyway).
PS: Gosh, that was a long sentence.