split bet payout wrong?

Made a split bet on 11/14 at a live table, expected a 17 to 1 payout if it hit. Ball lands on 11, they pay me 16 to 1 instead and the dealer just shrugs like that’s how it always is. I triple checked my scribbles at home and my spreadsheet says it should be 17 to 1 for splits, am I missing something obvious here or did my math brain get tripped up by the smoke and blinking lights?

Is there some weird house rule in some casinos where the payout gets tweaked or did the dealer just round down out of habit? Not my biggest loss but definitely felt like getting charged a convenience fee for having a brain. Wondering if anyone else ever had a split payout get shorted, or if I just look like the guy who needs a sign saying “confuse me” around my neck.