You can specify an Estimate phase for each bid component. It must be a valid phase set-up in your Phases File.
If you choose to print totals by Estimate phase (a separate report that comes out after printing a bid summary) the totals will be redistributed according to the Estimate phases you set-up here and in the Subtotals File.
If you set-up phase codes for subtotals, be careful when you set-up phase codes for bid components. Don't set-up a phase code for a bid component that references a subtotal. That would cause an amount to be added into an Estimate phase twice.