I read through the pattern a couple of times and I was confused by it too, but I've concluded that you don't knit any more even rows after the 3.75". I think it's just telling you that as you are doing the shaping, you are only going to do rows 1 and 2 of the pattern and that you don't do anymore cabling:
The reason the line of the pattern says "From this point"...
[I]From this point, work in 4x2 Rib as set (Rows 1 and 2 only); no further cable twists will be worked.
Shape Upper Edge:
Note: In the next series of rows, sts will be bound off at the beginning of RS rows. The last st of each WS row will be left unworked, and will be the first st in the row that follows; this will help give a smooth shape to the BO edge.
Row 1 [RS]: BO 12 sts, work in pattern to end. 100 sts.[/I]
I would suggest though, that you email the designer. I actually emailed her awhile back to ask her about yarn substitution for that pattern, and she responded right away and was really nice.