I’ve been observing a trend in several European and American software companies when it comes to salary negotiations. Basically, HR says we have a “formula" to calculate the salary for our employees according to their years of experience and the interviewers’ feedback. However, none of them ever let you see that formula. They just tell you that this is a fair way to calculate the salary for all employees so that people with the same experience have close salaries.
The duplicate question states how to determine a reasonable salary.