I read the answer to a previous question on this topic by @David-70 which said it was for changing the suction for various surfaces.  However, this answer raises several questions, for me at least, since the description of the V15 Detect Digital Motorbar says it automattically adjusts for various floor surfaces:

Questions

1. the center setting, which is the default setting, is an “upside down triangle”, is this the setting for “Automatic adjustment”?
2. If the answer is yes, then are the “+” and “-” setting for manually setting the suction to a higher or lower setting that won’t change for the various surfaces?
3. Is there somewhere on the Dyson website where I can read more about the Digital Motorbar?

Thank you in advance for your help

Michael