Lets say it's in the playoffs of a season and I'm doing my re-signs. I'm playing the slider bonus game and on the player screen it shows me as saving money each time I do it. However, the main re-negotiation screen keeps getting worse and worse in the negative. I don't feel like wrecking my teams and I saw some chatter about 'most of the salaries paid out at this point.' Basically, if my player screen is showing I saved am I good to go and thus ignore the main re-negotiation screen moving negative with each re-sign?

That doesn't sound right, I wonder if there's a bug there. If you're past week 16 it should not show that you can save money in the current season with a renegotiation. Future seasons, maybe, but not the current season.