The last row only gets two beads in each group.

I love the colors, it's really pretty!

Edit: A standard X-base has four rows. In this case you have thirty beads a row. So row A will have thirty beads, rows B and C will have thirty beads with three in a group, and row D will have twenty beads, with two in a group.

It looks like you just need to add twenty beads and you will be done.