1. Is the 4th type penalty still in existence?
2. If so, what defines a type? In my practice beginner world I have B737, PC12 and and Embraer fleet of 120s and 135s. I have just ordered a bunch of 777. Is "Boeing" 1 type, and Embraer another and Pilatus the 3rd? Or am I being hammered without realising it?
Look at your fleet commonality screen. They will be defined accurately here.
Pilatus is one fleet group
E120 is one fleet group
E135/140/145 is one fleet group
777 is one fleet group
737 is divided into 3 fleet groups : 100/200, 300/400/500, 600/700/800/900/MAX
That being said, the 4th fleet group penalty becomes annoying at 200 planes, and punitive around 400 planes. So, it depends on how big you think you'll end up. At worse, you can cut off your smaller planes(whose profit is usually small anyways). Flying both Pilatus & 777 makes sense only if based in Tahiti, or a similar island. What is your base airport?