Thank you both (Fred Smith and JoeU2004) for your responses. My apologies for
replying so late therefore have lost the thread!

What I am trying to compile is an Annuity Template where the user enters the
various parameters and all calculations are compiled automatically. How I
picked up the problem is that I have the following loan constants as an
example on which the template is being built.

120,000,000 PV - Total loan
30,000,000 FV - Balloon
8.25% i - Annual Interest
12 n - Monthly payments - Interest calculated at 8.25%/12
1 Jan 00 Start date
31 Dec 09 End date - Baloon payment date + last instalment
10 Term loan - 10 year repayment period
120 NPer - Periods
1 PPMT type - in advance

If you calculate on an arrears basis the total Principal repayments are 90mn
over the period (120 months) and the Balloon correctly stands at 30mn whereas
if you calculate for payments in advance the total repayments are
90,204,841.71 ??? and the Balloon stands at 29,795,158.29 ???

JoeU2004 your suggestion for the workaround equates to the first intalment
of 485,123.63 for principal which is the same result as using the Excel PPMT
function in arrears ("0").

What about the interest portion for the first instalment in the event that
the payment has to be made in advance? In my exercise this equates to "0"?.
Any suggestions on how to work around the interest portion?

The exercise is actually involved within the shipping industry where
Bareboat (Lease) Charters have to be paid monthly in advance.

Thanks in advance/sgl