The Take 5 pattern uses 5/8 yard of each of the 5 fabrics for the main body of the quilt. The additional yardage for the 2 chosen fabrics is to remain strictly for the borders, both inner and outer. By separating the 5/8 yard of the 2 fabrics at the start, you avoid getting it mixed up with the border fabric and possibly falling short later on. Which could be possible, depending on how the later cutting instructions are to be followed.