My plan administrators pays for 0% of my medical prem. insurance and I pay 100% of it through retirement payroll deductions. Am I eligible for the PSO deduction?

Deduct from your pension? - No.   The insurance payments must be paid by the pension plan administrator from the pension - not form other funds.

IRS Pub 575 page 6.

https://www.irs.gov/pub/irs-pdf/p575.pdf