Anyway I think Abiu, Star apple and C. Imperiale are more closely related than Abiu and other pouterias like Lucuma, mamey, Canistel etc.
If botanists agreed with this then abiu would be classified under Chrysophyllum.
If this was proven science we would have names that stick forever, instead I see way too often plants changing names and I am not talking of incorrect ID on this forum.
The same Chrysophyllum Imperiale we are talking here was :
1-Theophrasta imperialis
2-Martusiella imperialis
3-Chrysophyllum Imperiale
And now they want to go back to Martusiella, because some dna study revealed it is not closely related to neither Chrysophyllum nor Pouteria.
I am not a botanist, but the above is my point of view.