WITH A solid 4-to-1 vote, the Montgomery County Planning Board has decided that one of the most vigorously disputed projects in the county in recent years should be given six more months to sign up the necessary commercial interests for a $250 million retail, office and hotel complex. The decision came after developer Lloyd Moore presented evidence that one "anchor" for his project at Georgia Avenue and Colesville Road in Silver Spring has been secured: Macy's has agreed to put a store there. Mr. Moore now has been given until January to sign up another department store and other establishments.

Mr. Moore originally had been given until June 29 to provide evidence that he could bring in two big-name department stores. When the board voted for the extension last week, chairman Gus Bauman was the only member to vote against it, even though he voted for the project when it was approved in January. He said he opposed the extension because Silver Spring as well as the project have been in limbo long enough already.

But all sides in this debate have been parties to delays when it suited them. Board member Nancy Floreen, who has consistently opposed the project, favored the extension on this vote and offered a sound explanation for her decision: she pointed out that at this point it would be short-sighted to kill a project already endorsed twice by a majority of the board. That makes sense, while fixing a definite time for Mr. Moore to build on the progress he managed to make before his first deadline this month.