In the Houston area, where I have been a golf professional for the past 8 years, I have come to the conclusion and so have a lot of other people that the bermuda strains need not be overseeded in the winter.
It is better to have good greens in our peak seasons of March, April, May, September, October, and November than have "green" greens for December, January, February, and March, when we have typically our coldest weather. There is no competition then for the start of overseeding and no competition when the bermuda comes out of dormancy. Also, the past about 5 years, we have seen that our greens have only gone dormant for a few weeks to a month.
This is typical in our area, which is different than say, Florida, where their peak seasons are Dec-March and want the tourist play. Our area is not known for a ton of weekly golf groups traveling to Houston instead of Orlando.
Going back to bentgrass. The bermuda strains are more hardy, require less amount of money to keep "alive", and have saved courses countless of thousands of dollars in our area that have decided not to overseed and have not seen their conditions, or their bottom line suffer.