Does the auto-interrupt logic allow for fast-moving small ships to complete movement before the auto-interrupt occurs due to a new sensor contact? I've had some spoiler races going after one of my small colonies from time to time, so I have a small FAC fleet posted there to drive them off. My sensor FAC has an R200 sensor that detects out to 230m km, and an R1 sensor that detects out to 11m km. I've had twice now where I'm doing my normal 5-day time increments because of no contacts, to finish one 5-day where all of a sudden a spoiler race is on top of my colony, has destroyed my sensor FAC, and then the spoiler ship itself is destroyed by automatic STO fire. The spoiler race ship is small so the shorter-range R1 sensor would be required to detect it, but in other similar situations of the game, in most other cases the time increment stops advancing when the R1 sensor detects the approaching spoiler race ship, allowing my FACs to engage it off-colony.
After the first time this happened I clicked "Select Sub-Pulse Length (Auto)," although normally I don't change this setting. After a few other spoiler race fights I had the above situation issue happen a second time, where even though the R1 sensor was active the spoiler race was allowed to make it all the way to the colony before the time increment ended and destroyed another sensor FAC.
Is this normal behavior for large time increment advancements? My assumption was the game would automatically stop advancing point if it calculates a Hostile contact would be detected prior to the time increment completing. For now, I'm working around it by putting a lot of DSTs on colonies without better low-res active sensors available.
Ship detection is checked for after each sub-pulse.
The default sup-pulse length for 1-day increments is 30 minutes (
source).
It stands to reason that the default sub-pulse for 5-day increments is 3 hours (being the nearest option to 5 * 0.5 = 2.5 hours), but it is possibly 8 hours.
You can select a shorter sub pulse for your increment length (via that second row of buttons, just below the buttons for increment length).
There is some logic that ignores manual sub pulse selection if it is below a certain percent of the increment length, but I can't find the details. Maybe Steve can remind us?
So, you can either play with shorter increments or shorter sub-pulses, or you can deploy additional sensors to account for the full movement range possible for an enemy fleet of a given speed in the span of a given sub-pulse length.