What servo did you get the V-Power from Ruby? Was it a servo that is very busy? 98 ron fuel (no matter who makes it) will lose octane as it sits. So if it had sat in their tanks for 3-4 weeks because no one had bought it, then it would probably have been down around 95 RON.
The trick is ALWAYS buy your fuel (BP, Shell, Mobil) from a very busy servo. Tanks get drained quick, which always means nice fresh 98 ron fuel.
The same applies if you put you dont drive your car for a while. If it sits for a month or two, ALWAYS add fresh fuel, or at least octane booster before heading off again
Supporting the above, I've use both V-Power and BP Ultimate in all my cars, and each fuel is the same as each other - never a bad batch because I always visit busy servo's on main roads