Did you change the 5 default test frequencies used for alignment?
The default frequencies cover the entire band and are spread evenly at Low, Center and High values eg 405, 435, 470 MHz
I guess you can just input Low, Center and High values which, say, just cover 440-450MHz?
One issue with the UHF TK3180 is that the front end alignment process involves using default softpot values for some settings and then aligning on other settings..its a bit odd!!