It would probably be more accurate if instead of "Percentage" that they use "Flow Rate". But it is realistice by use anyways, besides that half the engines would/should probably over combust. So 50 would be 50% Flow Rate, meaning the Nitrous Oxcide would flow at half the "Flow Rate" as 100. Nothing corresponds with previous HP. Now for GT6, the **% means Flow Rate, Not HP increase. It would be stupid to say "Real Driving Sim" then use that number by HP, because that's not how real Nitrous Oxcide works. I hope this is understandable for all. 👍