Ctrl A not working after copy ?

I did a copy of an object
and it use the same mesh data
so the there are like 2 user for same mesh

ob8 = sphereyellow1.copy()
print ( ‘Before ob8 =’, ob8 )

now Ctrl-a does not work on multi user ob !

but overall does it save memory ?

when using multi user and Ctrl-a is not working
what about scale and dim for ob if needed

thanks