I've already heard from a reader who read One Man Advantage, and while she liked the story and had positive things to say about it, there was one aspect of the story that disappointed her, to the point where it impacted her overall experience reading the book.
To be honest, I'd wondered about this when I finished writing One Man Advantage. (For those who haven't read it, I'll try to talk about this without being spoilerish.) When I started writing this book, I'd thought the answer to this unanswered question would come to me as I wrote. I even asked some readers what they thought about it. Because another truth is, I don't even know the answer yet!
I'm mostly a "pantser", although I do plan the turning points of my stories - but those are based more on the emotion and the epiphany and the decision that has to happen for the character at that point, not actual plot events. Many plot events come to me as I write the story and get inside the heads of the characters. As this story unfolded, I brought in characters from past books briefly, but this was not their story - this was really Nicole's (and Logan's) story. I do see it mostly as Nicole's story, with her character growth being more than Logan's. And when the story ended, I realized there was no more opportunity to add something in that was really unrelated to Nicole's story.
I didn't do it deliberately to try to sell more books.
I asked my editor's opinion about this too, and she felt the story was fine the way it was.
Could I have gone back and changed things? Possibly…but when I look at the only scene where this could have happened, this scene was a turning point for Logan. That was his "black moment" where he believed he'd lost everything (again without giving spoiler details). If I'd added in that significant, life-changing event for a character who is really a minor character in this story (despite how attached we all may be to him from his own story!) this would have detracted from the impact of Logan's dark moment. At that point, the focus had to be on Logan, on what was happening with him and how he was dealing with it, and not on another character.
The other place I could have changed things up was the phone call between Logan and his mom, near the end of the story. But something that momentous seemed out of place there, during the resolution of Nicole and Logan's story.