Landscape in ground mounting - backlight exempt?

Sue, I don't understand your logic. This is the exemption in the credit:
"Building-mounted luminaires with the backlight oriented toward the building are exempt from the backlight rating requirement." Building-mounted fixtures don't have to comply with the "B" rating because their "back" can't be towards the lighting boundary. Everything else has to comply per Table 3. This is not a LEED interpretation issue

BUG ratings are designed for light fixtures that are aimed down.  Zero degrees nadir.  It is not applicable to ground mounted landscape fixtures that are aimed.  Lights that are adjustable up and down would need a new BUG rating for each angle degree tilt.  Hence the exception,

"lighting that is used solely for façade and landscape lighting in MLO lighting zones 3 and 4, and is automatically turned off from midnight until 6 a.m.;"

although the original  question may or may not be within scope ..i respectfully would not characterize it as illogical… i find the lack of coordination and consensus at the basic definition level among different individuals, groups, sdo’s and the numerous national and international codes, standards, recommended practices, guides, legislation and the like are oftentimes out of date and/or contradictory… when one attempts to thoughtfully address the negative effects of alan as the question does..shouldn’t we recognize that an abundance of “standards”contain..minimum requirements…i believe building green encourages practitioners who strive to go beyond minimums..and welcomes thought provoking questions, responses and solutions… artificial light at night awes, inspires, comforts and protects us all….my project involves the promulgation of local regulations to deal with some of its drawbacks in a fair, consistent and balanced way…kind of tough without up to date ansi definitions and mlo’s…am i not looking in the right place/s?

I have long complained that this credit is overly complicated.  I'm also not a fan of the BUG rating.  But it was an attempt to simplify.  To gain a consensus at a basic definition level.  And the lighting industry really seems to have adopted it.  It's a standard now.  Both responses were attempting to explain the LEED language.

I have once heard someone describe constuction "code" as a separate language.  The dangerous thing is how similar it is to (in this case) English language.  Most words in these two languages are similar but not identical.  While the English language often has multiple meanings for a single word, "code" language does not. There is a lot of confusion in different meanings of words when applied as code. 

In this case "building (wall) mounted".  Is it describing a category of light that we see when searching manufacturers' websites?  This is what I think the OP is using as the meaning.  A style of light fixture.  But as it is written in LEED, "building mounted" refers to a location the light is installed.  The style is irrelevant to LEED.

No one characterized OP as illogical.  And I don't see any rude response.  They are speaking different languages and being honest about not understanding each other's use of a word. 
 

I agree that it does not apply to ground-mounted landscape fixtures. However, the lighting industry seems to have adopted the BUG rating. Anyway, the BUG ratings are designed for light fixtures that are aimed down.