But sometimes the manual do lie.
The manual was written when the bike was fresh and all the testing and experimenting that was done was Honda's own. After 50-years, some ole farts have found what works best. As well, we now strictly use unleaded fuel, which effects some adjustments. Oil has also advanced.
Then there are discrepancies. Sometimes a manual will simply have a typo or incorrect procedures. It's good to have several manuals so you can cross-check them. The pre-K4 Honda manual is inconsistent in some regards to the K4 manual. Usually, you'll go with the later one, but sometimes they are model-specific.
I know it's confusing, but you'll eventually have a basic sense of what goes where and when.
Here's an example.
I don't know what octane rating you use there, but I doubt you will need 98 (R+M)/2.
I get this a LOT. I ask a customer "do you have fresh fuel in the tank." "YEP! Just filled up with premium, no regular crap."
I know the manual says 91-95 octane, too lazy to look, but that's the RON number. Most pumps will use the average of RON and MON, so at a pump that says (R+M)/2, 87 or 89 would be equivalent to the manual's RON number.
The idea is to use the lowest octane you can without knocking. No knock, no worries.
Also, premium does not "burn cleaner" than regular or lower octane fuels. So don't feel like you're feeding your bike crap just because it's cheep, and smile at the chump that's pouring "premium" into his Nissan.