When I laid out the original board for this project, there were no connections to the power plane. Since a 3 layer board is not a valid choice, I just doubled the ground plane. After the layout was complete, it occurred to me that there was very little routing on the back side of the board. After the initial 4 layer boards came back and worked, I removed the 2 ground planes and poured a plane on the back side of the board. This configuration cut the board cost in half. The new 2 layer boards came back from OSHPark yesterday, and I built one up this morning and tested it. It works as expected.