COS from H1 to L1 - one continuous year out of three requirement

Hi, I wanted to check what is the one continous year out of three requirement for an L1 visa application.

Basically the rule says that for an L1 application the employee (benificiary) must have worked for the company outside US for one out of three years continously.

My question is - this one out of three years, is it from the time of filing for H1 or from the time of entry to US? I ask this because as you might have figured, i am already in US on H1.

The USCIS website says preceding entry to US, however i have heard from the time of application.