No. Your company is doing it right. Although they had the option of reimbursing you in 2016, the fact that they choose to reimburse you in 2017 limits them to the $5250 ANNUAL limit on tax free reimbursement.
If you did not claim the Tuition credit, on your 2016 return, you may want to file an amended return to do so, since you were effectively reimbursed with after tax money