I think the pattern itself might be off.
Here's how I calculated this:
2.25 inch strips
first strip loses 1/4 inch to inside seam, so it is 2"
2nd and 3rd strip both loose 1/2 to both seams, so those are 1.75"
last strip loses 1/4 to inside seam, so it too is 2"
Which means:
2 + 1.75 + 1.75 + 2 = 7.5

Using the same logic, for your 1.5 strips, they need to be 4.5" long (1.25 + 1 + 1 + 1.25)
For the 1.75, they need to be 5.5" long (1.5 + 1.25 + 1.25 + 1.5)

Hope this helps!!