The easiest way to avoid being careless or too loose with terminology about Annona hybrids, is simply to call them "Annona Hybrids".
True "Atemoyas" ["ate" = Sugar-Apple", and "moya" is short for Cherimoya] are crosses of Annona squamosa with Annona cherimola, ONLY.
This word was coined by an early Annona hybridizer, over 100 years ago, for this type of cross. Either of these two species may be the seed parent or pollen parent, and the total ancestry may be in any proportion, such as 1/8 to 7/8 Sugar-Apple, or Cherimoya. So this definition is somewhat loose, but within reason, as a popular term.
What looses meaningfulness, is to allow, without objection, the word "atemoya" to be used for any Annona hybrid, or, even, as one now often sees, any non-Soursop Annona at all.
So the Annona Hybrid 47---18 is not an "atemoya". In my Annona breeder's specific terminology, it is a "Temoylata" [Atemoya seed parent, pollinated by Annona reticulata].