Sec 121b5 exclusion loophole

[Carlos Ptriawan]

I'm surprised after reading this article:
https://www.accountingweb.com/...

Basically, if you have rental (or primary -> rental) and turn to primary, and then sell the property after live there for two years, the non-qualified use ratio doesn't really matter (in other words it's tax-free) as long as :
- when you sell, you live in the property for 2 years or more AND
- if you married and the profit of the sale is less than $500k.

Is my understanding correct?