Any modern flipper coil has two windings. Low power to hold the flipper bat up and high power for the initial stroke that propels balls upward.
On pre-fliptronic games, pressing a flipper button would cause the high power to kick in, sending the flipper upwards. The EOS would register and the low power would take over to hold the bat up. In other words, the EOS was very important otherwise flippers would be held up by high power all the time!
With fliptronics, the computer regulates this switch and does not rely on the EOS anymore to switch from high to low power. It will do so automatically after a couple of milliseconds. It does hoever use the EOS switch to detect flipper drops (from fast balls) and to switch from high to low power earlier than the predefined couple of milliseconds.
In other words, a game like NGG does not rely on the EOS switch to change from the high power winding (initial flip) of the coil to the lower power (hold) winding.
How does the EOS work to detect a flipper bat drop? For example, if a ball falls down from a height on the flipper tip: the hold power will not be enough to keep the flipper up. The flipper will be pushed down just a bit from the impact of that ball and by this the EOS makes contact (opens/closes, depends on game generation). The computer senses this EOS state changes and performs another "power boost" for a couple of milliseconds by switching to the high power winding. This happens so quickly that it effectively prevents the flipper bat from going down more than maybe a millimeter. You shouldn't really notice this at all. After the power boost, the flipper is up again, the EOS is closed/opened again and low power takes over.
Now you'll hopefully also understand the importance of the EOS: if set to tight (activate too early in the flipper stroke) then the stroke will no be powerful because low power kicks in too soon. But it will also cause the flipper bat to be slow to react to ball impacts pushing it down. You'll notice in that case that a ball falling fast on an upright flipper will push the flipper down quite a bit. That's not good. In other words, this is where good EOS switch adjustment is very much needed!