Can we use Voting in Time Card approvals?

We have a requirement that when timecards with a specific costing string are entered it is sent to an approval group for approval, rather than to the users line manager.

We have set this up in the Transaction Console:

In testing the claims go to each member of the group for approval in turn. We would like to use Voting %'s similar to Expenses or Procurement requests to allow one member to approve on behalf of the group. However the Voting tab in the TimeCardApproval BPM task is greyed out, even when editing mode is enabled. Is it possible to use voting in this task?