My mom is a CPA, SM in Tax, and won't take anyone onto her team if they can't look through a list of allocations and correctly answer whether they do or do not

My mom is a CPA, SM in Tax, and won't take anyone onto her team if they can't look through a list of allocations and correctly answer whether they do or do not apply for Real Estate and Hospitality. She has had one person last more than three years on her team. But with 1/6th of the workforce of any other manager, her people have ranked top three annual billing and efficiency for the last 6 years. There are tests, but they're unconventional. And there are times I hear my mom pick up her office phone, call one of the firm's partners and say, "Stupid question. Would you allocate this to X or Y?" And then 40 minutes of heated debate over whether it will or won't cause a $300 penalty on a multi-million-dollar return. Maybe engineers need more unconventional tests?