It's not so much whether it'd be cheaper or not but more the fact that the airlines in Oz don't like CASA ATPL's that have been converted off the back of an FAA ATP. Too many guys took the easy way out in the past; they did a quickie ATP here in the States and then converted them to Australian licenses.

The Airlines were surprised that these ATPL holders didn't have the theoretical knowledge they'd come to expect. Hence they now all ask on their apps if you have converted from a foreign license and which country it was issued in.

As it would be illegal for them to discriminate against converted ATPL's they also ask if you have passes in all the ATPL subjects and require you to show your transcript at an interview.