Besides the obvious problem if the engine's thrusts are not exactly
tuned,
I take it they're firing the engines at a lower altitude.. this makes me think:-
- Higher G-forces to slow down.
- 3x engines running at lower thrust = lower efficiency = more fuel.
Compared to a single engine where...
- Higher thrust = more efficiency = less fuel.
- You can start higher with a more gradual G-load - preserving the stage more.
- Redundancy by way of only one engine failure is necessary in either case.
??
Maybe they're just testing different configurations.. but then again it's not
rocket science to work this out..