If you select 'Maximize' as the Allocation Type in the Allocation section of Tasks menu, you will then have have the option to select one participant, or all HCEs, to maximize. Also you can select to maximize to the 415 limit, or another lower amount. This option is available for all allocation formulas except for New Comparability.
With a New Comparability profit sharing formula, select 'Specified' as the Allocation Type. To achieve a maximum contribution you can enter a percentage or dollar amount under Set Allocation Parameters/Define Allocation Groups that will generate a maximum contribution for the group or groups that you want to maximize. The software will enforce the 415 limit so you can enter an amount or percentage larger than required.