2014 RockShox Pike RC oil recommendation
The Service Manual or the Air/Oil chart from SRAM are your most reliable sources.  This is the same source a SRAM/Rockshox dealer should be using to provide you this information, so there is no reason your LBS should offer you different information. 

As for YouTube, that source is only as trustworthy as the guy who made the video, and given the volumes you quoted, I’d say you should stick to SRAM support. 

Make sure you are paying attention to model year, since different model years may require different oil volumes. 

The air/oil chart for 2014 Rock shot suspension can be found here.