There's another post on this (s'ok, we don't care). And, yes, it IS confusing.
You're referring to the 2.5 models, btw. I've run both 89 and 93. I've "felt" the 89 actually ran better at times and have also thought the same with 93, so who TF really knows 🤷🏼♂️ ? I've not tried 87, but I...