It is not 400 MP and 30 fuel.
It is 200MP and 30 fuel. It is somewhat worth it. Considering also its timing.
I'll try to explain this again.
If you want to build 222, you need to build T2 (200 MP 20 FU) and then build the 222 (200 MP 30 FU). That's 400 MP 50 FU.
If you don't build a 222, you don't have to build T2 any more.
Therefore, the difference in price between building the 222 and not building the 222 is 400 MP 50 FU.