Why female session background singer Belinda West never sang backup behind ABBA

She was a studio background singer behind Larry Jon Wilson on:
New Beginnings (1975)

Tracklist:
Ohoopee River Bottomland 3:43
Through The Eyes Of Little Children 3:33
New Beginnings (Russian River Rainbow) 3:37
The Truth Ain't In You 3:13
Canoochee Revisited (Jesus Man) 4:31
Broomstraw Philosophers And Scuppernong Wine 3:12
Lay Me Down Again 3:23
Melt Not My Igloo 4:49
Things Ain't What They Used To Be (And Probably Never Was) 3:01
Bertrand My Son 3:28

Credits
Acoustic Bass – Henry Strzelecki
Acoustic Guitar – Johnny Christopher, Larry Jon Wilson
Gut Strings – Don Potter (tracks: B4)
Arranged By – Bergen White
Backing Vocals – Belinda West, Bruce Dees, Ginger Holladay, Janet Helm, Lea Jane Berinati, Mary Holladay
Bass – Tommy Cogbill
Cover, Illustration – Gene Wilkes
Design – Bill Barnes, Julie Holiner
Drums – Hayward Bishop, Jerry Carrigan (tracks: A1, A5)
Electric Guitar – Bruce Dees (tracks: A4), Reggie Young
Recording Engineer – Bruce Dees, Chip Young, Mike Shockley
Harmonica – Donnie Lowell
Keyboards – Bobby Woods
Personal Management – Michael B. Leonard
Mastered By – Mac Evans
Mixed By – Brent Maher
Percussion – Farrell Morris, Hayward Bishop
Cover Photos For Art Reference – Jimmy Thomas
Flyleaf – Shar Wainwright
Producer – Bruce Dees, Rob Galbraith
Horns – Gayle Whitfield, Tommy Smith
Steel Guitar – Lloyd Green
Vocals – Larry Jon Wilson
Words By, Music By – Larry Jon Wilson
https://www.discogs.com/release/25567...

and Let Me Sing My Song To You (1976)

Tracklist:
Drowning In The Mainstream 3:06
Let Me Sing My Song To You 3:04
Sheldon Churchyard 4:04
I Remember It Well 2:40
The Ballad Of Handy Mackey 3:03
Think I Feel A Hitchhike Coming On 2:40
Willoughby Grove 3:37
Life Of A Good Man 3:23
Kindred Spirit 2:14
Farther Along 4:18

Credits
Acoustic Guitar – Don Potter, Larry Jon Wilson
Arranged By – Archie Jordan
Art Direction, Photography – Ken Kim
Backing Vocals – Belinda West, Bruce Dees, Janet Helm
Bass – Tommy Cogbill
Dobro – Weldon Myrick
Drums – Hayward Bishop
Electric Guitar – Mac Gayden (tracks: A3), Reggie Young
Engineer – Brent Maher
Overdubs – Lowell Dorn
Harmonica – Donnie Lowell
Keyboards – Bobby Wood
Percussion – Farrell Morris
Piano – Bobby Ogdin
Producer – Bruce Dees, Rob Galbraith
Vocals – Larry Jon Wilson
https://www.discogs.com/release/25568...

She also sang backup in the studio behind Amy Grant on "Don't Give Up On Me" from her 1980 album, "Never Alone":

Don't Give Up On Me
Horns Arranged By – Don Hart
Backing Vocals – Belinda West, Brown Bannister, Bruce Dees, Patti Leatherwood
Bass – Bob Wray
Drums – Roger Clark
Electric Guitar – Bruce Dees
Fender Rhodes – Clayton Ivey
Music By – Brown Bannister
Acoustic Piano – Thomas Cain
Words By – Amy Grant, Gary Chapman
https://www.discogs.com/release/16265...

But no Belinda West singing backup behind Swedish pop supergroup ABBA on their 2 albums, "Super Trouper":
https://www.discogs.com/master/25734-...

and "The Visitors":
https://www.discogs.com/master/50014-...

Just ABBA alone on all vocals on both 2 albums of the same 2 names from 1980 and 1981.