exactly. salary is the only common denominator, hr only asks for previous salary, not previous rank which is meaningless

however, internally the rank does have added information that salary alone doesn't tell. take black/red bank for example, if possible one should ask for higher rank even at the cost of slightly lower salary. because once you are in, every year the benchmark is done at rank level. so if you take a lower rank of same salary, you'd appear to be well paid or overly paid, and end up with less increment/bonus. versus if you start with higher rank, hr will make sure you catch up soon. it's basically egalitarian although they call it balanced total compensation.