Process Direct Debits; performance improvements

The Process Direct Debits "Refresh" function has been updated as follows:

Instead of immediately getting the Account.Calculation, which causes a calculation of the future schedule and is time consuming, the Account.Calculation is loaded without doing a calculation.

If the total value to Direct Debit is more than 2 time the Account's current Balance (less any Residual Value) then the check to Limit the Direct Debit to the Account Balance + Accruals is omitted. This saves calculating the future Account Schedule.

From empirical testing this may make a 30% performance gain.