Because it is a foreign word, the person who transliterated "Doritos" into Hebrew used the samech /s/ instead of the sin /s/, so that there is no question that the last sound is an /s/, and not a shin /sh/. The Arabic transliterator used the sin /s/, and leaves it to the reader to be familiar enough with the word to know that it is not "Doritosh." Neither transliteration captures the American pronunciation of the assumed plural marker at the end of the word: [z], not [s] for "s." Photo of (used) wrapper follows.
You'll need to enlarge it in viewer to see the spellings lined up. Find them in the first word of the respective ingredients columns on the left-hand side of the Doritos wrapper. You can also find the kosher certification 2/3 of the way down. Standard English pronunciation ends the word in a [z] rather than the spelled "s"; Spanish uses a devoiced /z/ that sounds s-like. Apparently, both Arabic and Hebrew use the /s/, and I am lost as to whether that is a plural marker at all. Yum's the word!