Noro Gauge

I am using Noro Silk Garden yarn, the label states 4.5 sts per inch on a size 7 knitting needle.
My pattern calls for 4 sts per inch. I have tried a size 8 and a size 9 needle and I am getting 5 sts per inch. Could it be that I need to go to a size 10 to get gauge?
I am knitting in the round and have gauged in the round. It just seems like a big step to get gauge.

Marilynn

What needle size does the pattern say? And is the yarn the same weight as in the pattern? Some worsted weights are thicker than others.