After Palcic, the most common spelling variant of the name in the United States is Palcich. Other variants in the US and Canada include Palsic, Palsich, Palcie, and Paulcic.
In Slovenia, the surname is spelled with carons over each c (Palčič) to create a ch sound. Some families who immigrated to the US kept the surname unchanged without the carons, while others sought to preserve the sound of the name adding the letter h to the end of it.
The typical Croatian spelling substitutes an acute accent over the final c (Palčić), which produces a sound that is subtlely different from the Slovenian pronunciation. This subtle difference is difficult to detect for those who are not native speakers of Croatian. The name also occurs in Serbia with the initial caron and final acute accent.
A search of historical city directories in the United States yields the following variant and deviant spellings, some of the latter possibly based on the sound of the name as reported to the person recording the information for publication:
Variants in boldface type are in use today. The variant in italics shows a surname where the connection to the Palcic family is not verified. The variant in blue exists in one family descended from known Palcic immigrants from Slovenia. The Palsich variant can be traced back to a known Palcic immigrant from Slovenia. The remaining surnames appear to be deviants in historical records not used by any family in the past or present.
There may be a connection between Paulisich and Palcic, but so far, all I have for this theory is circumstantial evidence. I am also investigating the possibility of a connection between the Palcic and Pelcic surnames, but as yet have no positive or negative evidence.