Randall, that is my understanding also. I called this year to confirm it. I have a "Claims Made and Reported Policy" which I am told is standard in the industry for E&O insurance. I have had insurance with the same company (Affinity Insurance Services, which is a sub of CNA Surety) since 2010, and as long as I continue with them each year, I have coverage back to 2010. However, since this is a "claims Made and Reported Policy" if I don't continue with them, then I lose that coverage. Claims have to be made while the insurance is in force.
After research I see that the one I inquired about, Western Surety Co, is also a sub of CNA Surety, so I would guess the policy would be the same, so maybe I don't gain anything by changing - in fact lose coverage.