D252 - Two codes from one call are worth more than one code from two runs

status: measured

A note on method, because the sweep worked for a reason worth naming.

A single refusal code is nearly uninformative: it says a step failed. Two codes from neighbouring inputs bracket the cause. format=0 giving 0x80290003 where the baseline gives 0x80290015 says the format field is read and that the baseline format is fine - two facts from one extra call, neither available from any number of runs that only vary whether the whole thing worked.

That is why the variations differ from the baseline in exactly one argument. A sweep where two things change at once produces a table nobody can read.