Your charts show combined "A/R" roles which essentially guts the RACI model's utility.

RACI, properly implemented, means that the accountable party generally tells the responsible party "go ahead and do what you think is best, just call me when you need me. Also, I would like to be in the loop on items X, Y, and Z." (See also Bezos "Type I and Type II decision-making," which is RACI at is best.)

Well managed RACI is a lot simpler than setting an arbitrary threshold on things like spending thresholds, which would need to be defined for every single decision.