So-called judicial "tests" are so obviously malleable that they don't seem to drive the Court's results. It is sometimes too easy to see the Court's desired outcome dictating the application of its "test," rather than the test producing the outcome.
How would the First Circuit have ruled on the Spending Clause question if it had this precedent to rely on? We can't be sure. But I think the argument flows logically from Chief Justice Roberts' opinion in NFIB.