Can NM wire be used in a commercial building?

We have a suspended ceiling, that is going to be drywalled. Its steel framing and grid.

I just had 2 guys on a job working today and they ran NM for the recessed lighting?! They even fished it down a steel framed wall to the switch.

The Journeymen on site was assuring me its legal, cause its being drywalled and its not a 3 story building?

I have never tried running NM in commercial and never looked it up, but... Looking up 334.12, uses not permitted, (a)(2) says not permitted in, dropped or suspended ceilings.

Please confirm that these guys just wasted more than half a day doing it wrong.

Depends on the construction type. Section 334.10(3) allows NM in type III, IV an V constructed buildings when concealed with a 15 minute fire rated assembly.

A dropped ceiling that is drywalled is different than a accessible grid type drop ceiling...