Calculating true output of LED
Sorry, but you're out of luck. The manufacturer has no idea. They just slapped a bunch of IR LEDs into a housing and put it on the internet.

If you look closely at the specification list (such as it is) you'll notice that it claims a total power of 12 watts, which implies about 10 mA per LED. The 30 mA figure they sent you may (possibly) reflect an individual LED rating of a maximum current of 30 mA. Then again, it may not. Another giveaway is the specification "Power factor  850 nm".

So, trying to calculate the optical power is simply not going to work. The company doesn't know and doesn't care.

I suggest you're best off taking your typical 25 mW, multiplying by 96, and using that as a starting point. It's probably accurate to within a factor of 10. And, until you actually measure the output of one of these units, that's the best you're going to do.

Consider it a challenge.