Sterling marked "PAID"

I have inherited a flatware serving piece marked Sterling with no makers mark or hallmark apparent except for the stamp “PAID”. What does this mean? Is it an import or assay mark? The serving piece is engraved with the monogram of my married grandmother’s name, so it could be c. 1905 - 1910 or it could have been passed down to her from her husband’s family, who were from Stockholm, Sweden. Or it is possible none of this is correct and it is a randomly collected piece in my mother’s silver. Any help is much appreciated. I will repost with a picture when possible.