Computing $0 Payroll

SOLVED

Aloha,
S100C v19.5
I'm having trouble computing a zero net sum payroll record.
I'm trying to account for medical premiums we need to record, even if the employee doesn't work during the week being processed
I successfully computed and posted a nearly identical record last month, and even advanced the period without issue, but now I'm stuck.
I don't recall doing anything special last time.
Any suggestions?
Thanks,
~j