Where to report NON-taxable benefits paid?

My employees receive a non-taxable meal allowance daily (subsistence).  Although I have not deducted tax on this amount, the amount of subsistence is still included in total income box 14 of the T4 slip. Therefore, it shows that I did not withhold enough tax (even though I did).

Where should this amount be correctly reported on the T4, and why is it linking to box 14?