Why I sold a $20 September call option on Oracle

Yesterday I sold a $20 September call option part of my Oracle shares for 55¢ a share. As of this afternoon, they are selling for 65¢. Last year, I sold an option that was not exercised for these shares at 70¢, so I've created a synthetic dividend of $1.25 on a stock that earned 81¢. Now there's a risk (50.6% or so) that I will lose a percentage of that premium in accounting terms when the option expires. This option likely to be exercised, so it might be better to think of this as a sale of Oracle. I think Oracle is still undervalued, but I'm willing to sell because First Marblehead is even more undervalued.