Add UserForm textbox values

Hi

Im trying to add values which have been entered into a user form to get a grand total:

    Me.txtGrandTotal.Value = CDbl(txtTotalCost1.Value) + CDbl(txtTotalCost2.Value) + CDbl(txtTotalCost3.Value) + _
                                       CDbl(txtTotalCost4.Value) + CDbl(txtTotalCost5.Value) + CDbl(txtTotalCost6.Value) + _
                                       CDbl(txtTotalCost7.Value) + CDbl(txtTotalCost8.Value) + CDbl(txtTotalCost9.Value) + _
                                       CDbl(txtTotalCost10.Value)

I've tried it without converting to Double as shown above too and still no luck.

e.g. adding 567.78 and 12.32 gives me 567.7812.32 in the grand total text box.

Any help appreciated!!!