IS Sergeant First Class an equivalent to IDF - Samal rishon?

Great question, because in literal translation, the equation would be correct: "Samal" means "Sergeant," and "Rishon" means "First." However, in all branches of the Israeli military, the Samal Rishon rank is one step higher than the Samal rank. In other words, a Samal found worthy of promotion is moved up one rank to Samal Rishon. In the US Army and USMC, the rank that follows that of "Sergeant" is "Staff Sergeant." Israel's rank structure closely follows that of the US, with some fun exceptions that don't apply here. But more importantly, the Israeli "Samal Rishon"--while certainly an NCO (non-commissioned officer)--is not considered a Senior NCO like the (American or Israeli) Sergeant First Class. Thus Samal Rishon = Staff Sergeant, with all associated ramifications in terms of privileges and responsibilities. I'm very curious to find out how this came to be. After all, there is of course a Hebrew word for "Staff:" It's "Segel." So why isn't the Israeli Staff Sergeant called "Samal Segel?" Perhaps to confuse the enemy? So far, my research has not come up with a better answer than my tongue-in-cheek aforesaid one. P.S.: And, yes, I served as a Staff Sergeant....