Look at the full detail of the motif first. What you’re calling “round 2” seems to be “round 4.”
Given that, it does look like Round 4 goes like this: ch 4 (3 are the chs for the new round and 1 is for the round itself), dc, ch 9, sl st, ch 2, dc, ch 1 6 times, sl st.
It looks like there may be two possibilities for Round 5. One of them would assign the first three dcs to the first three chs and the last three dcs to the last three chs, with the intervening dcs and chs stitched into the ch-3 sp. The other goes like this: Ch 1, sc in ch-1 of prev. round, [dc 6, ch 3, dc 6 in ch-6 sp] 6 times.
That’s the motif itself. I’m not sure (without a key) what the filled-in chain-stitch symbol is that I see on the main diagram. They’re distributed on the ends of the petals wherever a petal joins to another. Maybe an extra sl st?