4 week Lull

Don't understand how I can go nearly a month without dropping but just a couple pounds . Started Aug 30 and weighed 268 dropped a lot very fast at first and am @ 237 now shooting for 225 . I'm a 6,4" male 52 yr old . Several users suggested I increase my calories , I was under 1700 with lots of walking exercise . I now eating bout 1800 to 1900 a day . Been doing different exercises besides walk in like shooting baskets or elliptical bout once a week . I thought it took 18 calories a pound to maintain weight , well 18 x 237 is more than 4000 calories I'm getting bout half that but not losing .