Question:
Are you planning to cut the Laurel Burch fabric into 6 inch squares - which would finish at 5.5 inches?
or
Are you planning to cut the Laurel Burch fabric into 6.5 inch square - which would finish at 6.0 inches?
The "math" for increasing or decreasing a component is usually figured on the "finished" size of the pieces, and then seam allowances are added.
Example: I have a 2-inch finished size that I want to increase to a 4-inch finished size - which would be a 2.5 inch cut size as compared to a 4.5 inch cut size.
I multiply 2* 2 which equals 4 - and then I add 1/4 inch to each side for seam allowances for a cut size of 4.5 inches.
If I double the cut size, the piece would be too large - that would be 2.5 * 2.5 = 5.0 - which would be too large.