
As per many times, and not unusual in the BR world, your lack of complete info is showing.
Firstly..The current form of Rumba was based upon 2 Americanised dances.. namely Bolero and Mambo . The ORIGINAL break pont in Mambo was taught on FOUR, and Bolero was "3".It changed in 46/47 to "2" .
The break in Mambo was changed to "2", primarily to co-incide with the clave strike on 2 of the 2nd bar ( as salsa is danced today and Son " which is 4 dominant " ).
So.. you only had half of the "story ". Most of the basic foundation steps in Bolero and Intern. style Rumba are identical, and, you can also add WCS as a contributor..
To add a little more confusion to the discussion, Rumba is really an all encompassing term ,and in reality ,is incorrect in its current usage .