DHCP Static mapped IP never offered

I suspect I am doing something incorrectly. I want my customers to use DHCP on their routers so I can reconfigure my network at some later date if needed. But, I want to statically map their IP's for bandwidth management upstream. (perhaps there is a better way to do that....) But, when I configure a statically mapped IP in the webui for their router's MAC address, the DHCP server does not respond when their router requests an IP via DHCP. Here is my DHCP config (names & IP's changed...):

ubnt@edge-rtr# show service dhcp-server 
 disabled false
 hostfile-update disable
 shared-network-name Public_DHCP {
     authoritative disable
     subnet XXX.YYY.53.240/28 {
         default-router XXX.YYY.53.241
         dns-server XXX.YYY.84.9
         dns-server 8.8.8.8
         lease 86400
         start XXX.YYY.53.247 {
             stop XXX.YYY.53.254
         }
         static-mapping ----------- {
             ip-address XXX.YYY.53.247
             mac-address 68:05:ca:1b:5e:26
         }
         static-mapping ------------ {
             ip-address XXX.YYY.53.246
             mac-address ac:9e:17:a9:b9:20
         }
         static-mapping ----------- {
             ip-address XXX.YYY.53.242
             mac-address 00:17:c5:bc:83:e1
         }
         static-mapping ------------- {
             ip-address XXX.YYY.53.243
             mac-address 04:a1:51:cc:ec:13
         }
         static-mapping ------------- {
             ip-address XXX.YYY.53.248
             mac-address 6c:70:9f:ce:f3:f0
         }
     }
 }