Hi! Speed bonuses work a bit different actually. Let's imagine that you're driving a car. Your final destination is in 50 km from your start point. You're going to reach it in 6 hours. 

It is necessary to start from the base speed. You have 50 km (this is 100% of the distance) and 6 hours (100% of the time). 

So, you have your base speed of 50/6 = 8.33 km / h. If your base speed increases by 50%, then now the speed is 8.33 * 1.5 = 12.495 km / h. This also means that now you can pass 150% of the distance in 100% of the time, and from these calculations you can count a new speed. 

Now you will pass 100% of the distance in 66% of the time. It means that by increasing the speed by 50%, you reduce the time by about a third. Previously, the time was 6 hours, and the speed was 8.33 km / h, and now the speed is 12.5 km / h (after rounding). And the time will be 50 / 12,5 = 4 hours.

Hope these calculations will be helpful!

Hello, thank you for your reply.

So the correct method to calculate speed bonuses is;

Variable1 x (Base Speed% + Modifier Speed%).

Thank you for the clarification.