Once a matter has been enabled for eBilling in CosmoLex, you would need to start using task code and activity code for each and every time card. Normally, standard UTBMS codes are used for this purpose but it is possible that your clients might have specified different codes to be used. In CosmoLex, you can enable UTBMS codes without enabling eBilling.
For the LEDES 98B format, each fee transaction needs both a task code and an activity code. Each expense transaction has an expense code.