One big plate is not always the efficient choice it looks like
Printing every part in one large batch looks efficient on paper: one setup, one job, one monitoring window. But a single failure partway through a grouped job can affect or waste the entire plate, and parts printed closely together can interfere with each other's cooling, especially tall or overhang-heavy parts near shorter ones. Sequential or small-group printing costs more total setup overhead but contains failures and can deliver finished parts incrementally rather than all at the very end.
How the plan works
Higher per-part failure risk and a need for individual delivery timing both push toward sequential printing, since containing a failure and getting parts as they finish both matter more under those conditions. A larger part count and no timing constraint push toward grouping for efficiency, but closely spaced parts pull back toward sequential printing, since cooling interference risk rises with proximity regardless of how efficient grouping looks on paper.
Worked example
8 parts, medium failure risk, no individual delivery timing needed, comfortable spacing if grouped: the tool recommends grouped printing, since the part count favors efficiency and neither the failure risk nor the delivery timing pushes strongly toward sequential printing here, with printing just the highest-risk parts separately offered as a middle-ground alternative.
A common mistake
A frequent planning error is grouping parts purely to save setup time without checking whether they will actually cool independently on the plate. Two tall parts placed close together can each shadow the other's part-cooling airflow, causing warping or poor overhangs that would not have happened printed separately, turning an efficiency win into a wasted plate.
Limitations
This compares sequential and grouped arrangement qualitatively based on the factors you describe; it does not calculate actual total print time or failure probability for your specific parts and printer.