I am currently doing my PhD in Switzerland. Since my professor recently get a job in Germany and will move the whole lab there, I need to go with her. That brings up to the question of working experience on the table. Both in Switzerland and Germany, the salary increase with the year of PhD. However, I am not sure if I move to Germany I would be counted as the level starting from the first year or they will consider the time I already had in Switzerland. Anyone has related experience?
You will have to ask the administration, or ask your advisor to ask the administration. Unless you transfer within Germany, this is decided on a per-case basis. But in principle, if you have equivalent experience to the current position (which you do), this should be feasible. However, as also pointed out in the comments, you will only get the corresponding level, but with all likelihood you won't get the runtime within the level counted. It might help if you add how much time you spent on your PhD in Switzerland at the point at which you will move.