WASHINGTON (Reuters) – The top U.S. telecommunications regulator is deeply troubled by Verizon Communications Incs recent announcement that high-speed wireless customers who subscribe to legacy unlimited data plans might experience slower speeds starting Oct. 1. I am deeply troubled by your July 25, 2014 announcement that Verizon Wireless intends to slow down some customers data speeds on your 4G LTE network starting in October 2014, Federal Communications Commission Chairman Tom Wheeler wrote Verizon Wireless President and CEO Daniel Mead on Wednesday. …