Nostrification - Do I need to do the process again if transfering to another Polish university?

I am currently studying in Poland, and I already have nostrification of my high school transcript. Now I would like to transfer to another university (also in Poland). Do I need to do the process again? Or the nostrification is done just once?

You may try to apply for an exemption from nostrification to the council of the university - if both schools are similar then it's better chance that your request will be accepted. I didn't found any information about double nostrification for different schools in Poland..

Would it not be easier to ask the University for advice?
You cannot tell them, that some unknown stranger on a website has told you that you don't need to go through the process again if they themselves say that you do...