Yes it says 98 on the 370 cap too, but the advice from people including Mark at Abbey is that 97 and above is fine. I've used 97 in all three of my 370s because that's the RON of the non standard stuff at my usual fill up station (Esso). I dont think 97 RON is routinely available in Japanese petrol stations, which might explain the reference to 98 on the 370 cap(?)
The key thing is to avoid the standard stuff.