The top Democrat of the House Financial Services Committee has “concerns” and wants answers from Fannie Mae’s regulator as to why it pulled the plug on the GSE’s plans to lower the cost of force-placed insurance. Rep. Maxine Waters, D-CA, the committee’s ranking member, dispatched a letter this week to Federal Housing Finance Agency Acting Director Edward DeMarco seeking an explanation as to why the Finance Agency abruptly shut down a plan pushed by Fannie…