Value Passed to Payroll - Standard Rate Set Up

Can anyone provide an explanation of the options available under "Value Passed to Payroll" on the Standard Rates>Processing Information tab?  The values are:

Annual Amount

Communicated Amount

Defined Amount

Estimated Per Pay Period Amount

Per Pay Period Amount

I cannot find a good description of the functionality behind each option and why you would choose one over another.  We communicate our benefit charges to employees as monthly amounts but then our elements have rules so that health is divided over two checks but life and dental come out as lump sums for the month on a single check.  We are on 26 pay periods a year so in months with three checks there are no benefit deductions on the third check (except FSA since it's a per pay check deduction).