These numbers (in red) will not work for size 18.5.
Rnd 9: Ch 1, fpdc around same fpdc, sk next fptr, fptr around first fpdc of next 3-fpdc group, sc in next sc, skipping fpdc that fptr was worked around, 3 fpdc around next fpdc (the center fpdc), sk next fpdc, sc in next sc, fptr around skipped fpdc (last fpdc of same 3-fpdc group), sk next fptr, fpdc around next fpdc, sc in each of next 1 [2, 2, 2, 2] sc, work 1 [1, 1, 2, 3] sc in next sc, sc in each of next 1 [2, 2, 2, 2] sc, *fpdc around next fpdc, sk next fptr, fptr around first fpdc of next 3-fpdc group, sc in next sc, skipping next fpdc that fptr was worked around, 3 fpdc around next fpdc (the center fpdc), sk next fpdc, sc in next sc, fptr around last fpdc of same 3-fpdc group (this is the last fpdc of the 3-fpdc group), sk next fptr, fpdc around next fpdc, sc in each of next 1 [2, 2, 2, 2] sc, work 1 [1, 1, 2, 3] sc in next sc, sc in each of next 1 [2, 2, 2, 2] sc, rep from * around, join with sl st to top of first fpdc–– 25 fpdc, 10 fptr, 25 [30, 35, 40, 45] sc.
**Please note: Rnd 8 = 4 sc (shown in blue below). Rnd 9 assumes there are 5 sc to work into (above in red).
Rnd 8: ...sc in next sc, work 1 [2, 3, 3, 3] sc in next sc, sc in next sc,...