No, I didn't discuss with her. This is my opinion.
I felt the relationship of fucboy and Sakura had a big gap as you mention Sukura changed his calling from "Yuma kun" to "Yuma san", they didn't live together and when the blond asked him how the relationship go, the fucboy's answer is "not so good".
I assumed sex between Sakura x fucboy and Fumi x Shinobu are both one-time sex.
Also, there was no agreement after sex to officially going out. Sakura let fucboy think she's his girlfriend while Shinobu let Fumi think she's his girlfriend.
And Sakura never said "I love you" to fucboy and Shinobu never said "I love you" to Fumi as well.
Fucboy realized Sakura will never love him by her neglect of his opinion while Fumi realized when seeing the pen.
I think Kodansha gave AK (sensei) a second chance with chapter 132 by Nagi's appearance. But the chapter 133, the meeting of Sakura Nagi and Mio, didn't work and Kodansha said it's enought to cut it short in chapter 136.
BTW, my Kodansha friend said since chapter 132 that the coming of Nagi shew her the author wanted to play with the misunderstanding issue and it meant Grapara will have at least volume 15. But it turned out to be the volume 14 will be the last volume by the failure of chapter 133.
IMHO, the purpose of chapter 134-135 were to break the relationship between Sakura and fucboy and Shinobu and Fumi and rush ending Shinobu with Sakura to save the volume 1-10 from being burnt as Japanese readers love to protest the bad ending by burning the manga !
If you want Sakura to end up with fucboy and Shinobu end up with Fumi, the volume 1-10 are useless, you really don't have to read them, right ?