On the Schedule of Benefits section of the Datair report there is a Monthly Benefit column and there is an Accrued Benefit column. What is the difference between the two? Is the Monthly Benefit the benefit if the participant works until NRD? And the accrued benefit is the benefit accrued to date?

Yes. But, I believe the monthly benefit does not reflect any salary scale in the projection to NRD (double check this if it is relevant for your case, as I could be wrong). Don't ask me why it does not say "projected". I'm a DATAIR supporter/user and like their fee structure, and they generally do things well, but there are a few quirks like this. Reminds me of Microsoft Word - page formatting is on the file menu - its so illogical but it remains there year after year.

The projected benefit in the Datair illustration is appropriate for some purposes, especially for life insurance based on projected benefit. Note that the projected benefit is not the same as the projected funding benefit under projected costs methods, of which FAS 87 is the only one still important since PPA.