S4 LED Power Thru limits

In the fine print of the Source Four LED User Manual v.1.8.0a (dated Nov. 2015) page 10 and 81 it says:

"No more than nine total Source Four LED (four total Series 2 Lustr) fixtures on Power Thru"

But on the *datasheet* dated Jan. 2016 it says:

"Up to nine Lustr or seven Daylight HD/Tungsten HD luminaires
(15A max) may be linked via power thru connector (10 Lustr
or 8 Daylight HD/Tungsten HD fixtures total per circuit) when
used with R20 Relay Module or Unison® Echo™ Relay Panel"

So can someone confirm what the real limit is - and even better tell us all the criteria? Is it just fixture wattage vs. the 15 amp rating of the supplied 14/3 PowerCon fixture cable, or does inrush current play a part?

Considering the range in wattage of all the S4 LED fixtures, maybe this Power Thru limit belongs in the chart on page 11?

And please note this limitation is not mentioned at all in the ColorSource documentation.

Finally, why is the supplied PowerCon fixture cable type SJTOW when we are hearing about greater enforcement of the NEC ban on "Junior Hard Service" cable use in theatres?

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