Interesting you thought that dear Rasoul, I can see many parallels in scent, but even more so the density of resination that occurs in both cumingiana as well as beccariana are quite similar. Even though we call it Aquilaria Cumingiana, it's doesn't exactly fit into the Aquilara genus.
In the past it was identified as a third genus designated as "Gyrinopsis", then later it was identified as Aquilara, after Aquilara Hirta was discovered. Comparisons were made between the two species, and they found that the perianth tube of of Cumingiana and Hirta were very similar, and that fruit grew in a similar manner on both species. Further consolidation of the Cumingiana species under the Aquilara genus occurred when comparing the number of stamens with other species (Aquilaria usually has 10, Gyrinops only 5), and as Cumingiana has 10 stamens, it made sense it'd be Aquilara...Right? Wrong
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The mature fruit of Aquilaria is usually green, while mature fruit of Gyrinops is orange/yellow. As for Cumingiana, well.. the mature fruits are brown/orange in color, but fruit color isn't a key charachteristic in taxonomy. Even Aquilaria Filaria has 10 stamens with orange fruit.
To further add to confusion, on a genetic level, Cumingiana is a lot more closely related to Gyrinops, based on both ITS sequences (Internal transcribed spacer) as wel as trnL-trnF sequences (chloroplast).
So.. there's Aquilaria, Gyrinops, and there used to be a third Gyrinopsis genus, guess it was for good reason.