Fiber Optic → [Fiber Pics] OTDR Calibration- standards?

Hello everybody,
I am interested in all compatible standards considering OTDR Calibration.
So far I managed to find out that there is IEC 61746-1 standard for Calibration, and also TIA/EIA-455-226 wich is adoption of IEC 61746-1.
And I concluded that those 2 are surely internationally approved and do the same thing.

I found in some website the offer for calibration performing both NIST traceable, and TIA 455.
I could not find out what is relation between TIA and NIST traceable calibration standards ( if there are any), is it the same or those 2 are compatible (if u use one of those for OTDR calibration it is enough)or those 2 are different and you need to perform both.

Then I found some NPL in UK that use its own NPL Fiber Attenuation Standard on their website, but it's mentioned that this one is compatible to any other standard.

Are there any for example Asian standards that are not compliant to those 2 europian and US standards that I recognized so far?
I apologize for bad english and confusing question.

Any info is welcomed.
Thanks in advance!