nyc doitt

Is there a fix for UHF trunk systems to accept 6.25 spacing? My 163/164 receive the NYC DoITT 400 mhz system fine because I can set the spacing to 6.25, however the 160 only goes down to 12.5 and ARC160 does 12.5, 10 and 5 but not 6.25. The manual shows this: "400-512 6.25 kHz " but does not...