How to get Coverage amount entered on screen into Rate Calculation Fast Formula

Summary: We have a requirement where Final Rate = Coverage * Some_DBI. DBI BEN_PEN_BNFT_AMT returns zero on clicking OK. Although it calculates perfectly with the 'Submit' button.

Content (required):

We have defined Plan1 (Basic) which is a multiple of Coverage and Annual Compensation. Employee Select Coverage1 % as at the time of enrollment; Rate1 = Cvg1*Ann_Sal

We have defined Plan2 (HRA) which is a multiple of Coverage and Rate1. Employee Select Coverage2 % as at the time of enrollment; Rate2 = Cvg2*Rate1

Basic Rate (Plan1) calculation happens immediately as soon as cvg is selected.

HRA Rate (Plan1) calculation happens only at the last step of 'Submit'.