Step 18 is not correct.
For example, the stock Hayabusa's intake cam opening is listed as 32 degrees and the closing as 64 degrees.
32+64 = 96
96/2 = 48
I take the opening number, closing number, add 180, divide by 2, then subtract the smaller of the two numbers.
32+64 = 96
96+180 = 276
276/2 = 138
138-32 = 106
Which of the two #'s seems correct?