Yes. RRSP Dedeuction limit is based on 18% of Employment Income.

Thanks for your response.
Is the severance amount in Box 67 considered employment income as turbo tax is calculating my 2018 RRSP allowance is 18% but based only on the income in Box 14.
Is that correct?

It is only based on box 14 amounts from a T4, or equivalent eligible amounts.
Severance wouldn't qualify.