Not only are tax interpretations increasingly difficult to obtain, but the tax office may unexpectedly change a position that has already been issued. Since the beginning of the year, the head of the National Tax Administration has changed 99 interpretations ex officio, several years after their issuance. There is no problem if it is a positive change – you can then recover the overpaid tax. However, if the change is unfavorable, an additional payment may be necessary.
Source Prawo.pl