Let's say I tell her that I have got something else to do and we'll make plans for the next time she realizes her mistake and apologizes, do I still go through with the soft next, or let her stay?
If it's a sincere apology, yes. If she's playing you like she was taught to play her Daddy by the age of 5. No. If you can't tell the difference, you will have to wait until the next time she does it.
Only respect sincerity in your girl, which you then reward with doting attention, which ultimately means orgasms. Never reward bad behaviour. Respect yourself.
By the way, was this good now?
What I'm describing is a logical response to a casual occurrence. Meaning, no emotion. That's the tone. You won't get it until you genuinely believe in and respect yourself. Until then, you act as if you have 50 women blowing up your phone. A girl is at your place and doesn't want to advance. What does that man say.
You'll get it eventually, for now use this: "OK. Well thank you for a Great time tonight."
She'll naturally be confused and either get out or prove why she should stay. She may start a fight though, again don't get a emotional, which is why I told you not to use your versions. Instead, you say, "I'm sorry you feel that" in a clear tone. As if you were saying, "It's raining outside".