i suppose so but it asks for 354 forge points to claim first spot, what i am asking is how do they arrive at a figure of 354
It is the reward x 1.9. The number 1.9 is arrived at because that's the return a level 80 arc gives you (rewards increased by 90%). Some have 1.8 threads instead, so it will be a 1.8 multiple instead.
In other words, if you have a level 80 arc, you break even on the fp, and get the prints and medals. If your arc is bigger, you get a profit. If it's smaller, you take a loss (so typically take the P4/P5 spots for prints).