Often your polars (you can usually get polars from other owners, or from USSA) will show that you should drop from a 150 to a 100, and/or put the first reef in the main, in speeds as low as 12-14 knots. Yes, sometimes it really is that low and you can pick up speed by doing it. (I don't know about your boat, just generalizing.)
If you can't get polars, experiment. Reef and unreef, get practiced at it, and compare boat speeds and wind speeds.
This is the first time I have heard the term "polars." What does it mean? What are polars?