A CL65 FLT CREW FAIL TO MEET A DSCNT XING RESTR IN ZID AIRSPACE.

Narrative

ATC GAVE US A XING RESTR; FL250; 80 NM S OF DQN. WE WERE ENRTE FROM ATL TO TOL. CAPT WAS PNF AND MADE RADIO CALLS AND SET ALT IN ALT ALERTER/FMS XING RESTR. FO ACKNOWLEDGED. FMS VNAV INFO WAS SET TO FO'S SIDE; HOWEVER; CAPT DIDN'T REALIZE THAT HIS (FO'S) 'SCALE' WAS SET TO ONLY 20 NM. XING RESTR CAME AND WENT WITHOUT CAPT NOTICING; FOR LACK OF VNAV INFO. FO WAS TEMPORARILY DISTR WHILE LOOKING UP INFO RELATIVE TO AN UPCOMING PROFICIENCY CHK RIDE. CTR FREQ CHANGE WAS MADE AND XING RESTR RPTED. LATER; NEW ATC FREQ QUERIED ABOUT OUR XING RESTR WHEN ASSIGNING US TO FL240. THAT IS WHEN WE REALIZED WE HAD NEVER INITIATED OUR DSCNT FROM FL280 TO FL250 BECAUSE: A) FO'S SCALE SETTING ON FMS WAS SET TO 20 NM; NOT ALLOWING PROPER MONITORING OF UPCOMING 'TOD' POINT; B) FO WAS DISTR BY READING POH; C) CAPT WAS NOT MONITORING FO CLOSELY ENOUGH OR MAINTAINING SUFFICIENT 'SITUATIONAL AWARENESS.' ATC TOLD US IT WAS 'NOT A PROB;' JUST WANTED US TO KNOW WE'D MISSED OUR XING RESTR. IT WAS A LATE NIGHT FLT AND NOT A LOT OF TFC WAS OPERATING. ATC ALSO FAILED TO NOTICE THAT WE'D NEVER BEGUN OUR DSCNT; WHEN; USUALLY; IF HEAVIER TFC IS BEING EXPERIENCED; THEY WILL PROMPT US TO BEGIN DSCNT.