No, I had my Formers raising the land on the adjacent SW/NE tiles to the base, which appeared to raise everything in the vicinity except the base tile, which remained at 10m. I reloaded a save prior to the terraforming and decided to just complete the Pressure Dome instead and live with it.
When I eventually got the notice of sea levels changing, the base was now higher than it was before, and no other change to coastal tiles was apparent. It was very odd. Is the rising/lowering sea levels mechanic somewhat bugged in SMAC, perhaps?