It's very hard to read when written in paragraph forum so I rewrote it out properly. Now if you look at it you can see that row 4 and 5 are the same. I think it must be a misprint because if you've been decreasing as written you wouldn't have enough as you found out. IMO it should be
R5: k2tog, k4 continue around;
R6: k2tog, k3 continue around, etc.
Each row has one less stitch in beween decreases. This is similar to hat decreases.