OZ Junglejet, I still don't think it stacks up. I've put together a very, very basic look at it. This is generic and not based on SunEx particularly.
A fleet of 3 x Metro 3 flying 4500 hours a year (at approx $600 p.h.) DOC = $2.7m
A fleet of 3 x EMB 120 flying 3850 hours a year (at approx $900 p.h.) DOC = $3.4m
This is excluding crew, insurance, intro costs & leasing. A roughie on leasing would be an additional $15K per month per aircraft. An additional $45K per month. A further $540,000 p.a. over the Metro.
Most regional airlines are on a contract fuel price regardless of location. I don't think the other savings you indicate would offset too much.
Just on these figures this equates to $1.3m per annum. An additional $25K per week. The big question is: Are SunEx offloading more than $25K a week worth of business?