While I agree with the general thrust of this forum there are some problems for large long lead time low volume items. For example:
I am currently importing aircraft from overseas which are sold to me in US$ with a considerable lead time and three percentage payments on order, 60 day, and when ready for shipping. Since I have no idea what the exchange rates will be on these three dates, nor the actual fraight rate or port costs when shipped and actually arrive at my hanger, there is no way I can quote a A$ price including GST, WITHOUT ADDING A LARGER MARGIN to cover the unexpected.
I do not consider this satisfactory.
What I do is quote a price in US$ and state to a potential purchaser: convert to A$ using the exchange rate you think it will be remembering to factor in the Bank's percentage; add 10% for GST; then add a average figure I supply which I have obtained from two Companies as an INDERCATION of expected freight and port costs likely to be incured, noting you may only have to pay half if another aircraft is ready to ship in the same container (ie. container can hold two). Allow for minor other costs (ie. RAA aircraft rego). Due to these variables without an explanation when contacted by an interested party, a price such as "FOB at factory" is meaningless.
Another area that prevents a firm price is if the purchaser wants their own avionics or other items fitted which are not in the standard aircraft or on the option list (thus in US$ which can be included in the initial conversion). This prevents the firm pricing even after adding a larger margin as the cost of the item changes so much due to the exchange rate (look at advertised prices of Garmin 296 GPS's for last 12 months!) and fitting costs can change even more!.
While "drive away, no more to pay" sounds good the only way to do it (and remain in business) in the situation I have described is to add a suitable (LARGER) margin.
Please, if there is a better way for the situation I have described, let me know.