I showed this recipe to my mum: Shanika
She says this is "very correct".
We call it Thuna Paha or three five in Sinhalese language.
Pronounced: Two - Ner (as in "ner-d") and Pa (as in "pa-pa") and Hah--
"Two-Ner Pa-Ha".
"Masala" is an Indian word.
The reason behind 3 -5 is a mystery..
It could be because there are multiple ingredients as you have listed out.
https://youtu.be/UY3GqyAslsA
There is a good restaurant in Water's Edge called Thuna Paha which we can visit.
We can ask the chef what the meaning behind 3 - 5 is when you visit.
It goes very well with curry cuttlefish -- which is one of my favourite dishes in Thuna Paha restaurant.