33.5 makes sense - a large pitta is ~11 syns and a couple tbsp of full-fat mayo is another ~10 syns!
Lamb doner kebab meat with salad is only 12.5 syns according to the app.
I had a chicken kebab recently, asked for no sauce and no pitta, and counted it as 12.5. I just put some extra light mayo on it when I got home and I was under my syns for the day!