In Rhode Island, at least, census-takers interchanged the names PELOQUIN and POLIQUIN frequently. My grand-pepere was a POLIQUIN until the 1930 census, when suddenly the entire family was listed as PELOQUIN. The error may have been made because Grand-pepere had passed away between the 1920 and 1930 censuses and wasn't around to correct the spelling. The family's name in Quebec was POLIQUIN.
When my pepere joined the military in WWII, he was signed as a PELOQUIN, because that was the name on his government documents; however, he had known himself as a POLIQUIN up until then.