private void RefreshSAProperties()
{
var ia = SelectedInvoices.ToArray();
AverageHoursWorked = Analyser.AverageHoursWorked(ia);
AverageOrdersDelivered = Analyser.AverageOrdersPerInvoice(ia);
AverageDropFees = Analyser.AverageDropFees(ia);
AverageTips = Analyser.AverageTips(ia);
AverageTotal = Analyser.AverageTotal(ia);
HourlyEarnings = Analyser.HourlyEarnings(ia);
OrdersPerHour = Analyser.OrdersPerHour(ia);
AverageOrderFee = Analyser.AverageOrderFee(ia);
AverageTipPerOrder = Analyser.TipPerOrder(ia);
OrdersPerTip = Analyser.OrdersPerTip(ia);
DaysWorked = Analyser.DaysWorked(ia);
AverageShiftDeliveries = Analyser.AverageOrdersPerShift(ia);
AverageShiftLength = Analyser.AverageShiftLength(ia);
}