FTE Savings Calculation

I’ve been recommending the various UiPath promoted FTE calculator spreadsheets included in the Academy etc but I’ve recently unpicked the formulae and have some concerns. From what I can see the formula is (basically) the starting FTE, depricated by weighted feasibility criteria, minus the exceptions. The volume/AHT/frequency criteria do not appear to come into the calculation. So if for example we had 20 FTE working with a process that was fully automatable, the calculator would suggest most FTE could be saved. But what if that team only spend 5% of their time on that process?? What if it only runs once in a blue moon? Is this calculation also carried through as-is to the Automation Hub? If challenged I need to be able to support the output of these tools with confidence!