knitting: designing lace medallion & placement of increases

I'm designing a lace medallion with six-fold symmetry. According to "Mary Thomas's Book of Knitting Patterns", this means that I should be increasing once-per-section, every-other-round, for a total of six increases every two rounds.

If in each section I decrease once and then increase twice, every two rounds, is that going to interfere with the knitting's flatness? The total number of stitches increased over the two rounds is still 6.

( the chart would look like this... )