Slightest clue? Yes. Much time ago you said that you made machines not lose progress for several ticks after [chunk] load. My memory (an unreliable thing) says that boilers started misbehaving on chunk load approximately after that.
Only applies to Basic Machines, nothign else.
And more Steam means 1.5x afaik. Engines might get stuck and THEN you have a huge Issue if you dont havea Pressure Valve.