Entitlement ????

I am a TCD and have been since May 2006. I didn't earn my 156 reports to qualify for my fulltime vacation. Now 2007 I drove and hurt myself in mid September and still didn't qualify for my fulltime vacation.I had them check my attendance record for the year and from Jan to mid Sept i accumulated 153 reports; 3 shy. I noticed that the day after I hurt myself the center coded me as scheduled off for the remaining 3 1/2 months. I had no loss of time and been on light duty since and getting my 8 hours+ as i was when driving.I'll shuttle ground out or deliver packages under 20 lbs. When following up the center said they coded me as a clerk for those 3 1/2 months in question and since it is coded out that way my those reports don't count towards my TCD reports. Is this a legit claim? I spoke to center manager and he said i will not get my fulltime vacation only my part-time vacation. I never went out on workers comp. Do i have a legit claim to take to the union? Any help will be appreciated.