Sorry Bruce - but I don �t quite understand what you mean in relation to this lesson.
Do you mean where they say 999 = nine hundred and ninety nine? This is how we say it here. Maybe SBE and SAE are different in regards to this.
In your example we would say four hundred thousand and three if it had no decimal place (400 003) and four hundred point oh oh three if it had a decimal place to three places (400.003). In fact, I think your second example is beyond what most ESL learners need because I don�t quite understand how you got the .403 from 400 003 myself (sorry but maths is not my strong point). I can �t see any reference to numbers with decimal points in this lesson.
Cheers
Jayho
EDIT: I�ve just clarified it with Swan�s Practical English Usage 389.10
UK English: always put �and� between hundred/thousand/million numbers below a hundred.
US English: �and� can be dropped
As this is a BBC lesson the usage is correct for those teaching/using SBE. Anyone teaching/using SAE will need to adapt it accordingly.