Have you read the instructions on how to use the MPRT indicator test?
https://testufo.com/mprt#pps=240&number=decimal
Instructions are in the text description.
Instructions: Your MPRT is the pair of vertical bars that touches edge-to-edge without overlap or gap. If all lines has a gap, please increase Pixels Per Sec.
Set Values Always decimal.
To understand how the test works, set your monitor to 60Hz and the test speed to 240 pixels per second. moving from left to righ
The length of one frame. the MPRT value
1000ms/60hz= 16,66ms per 1 hz MPRT value
1000ms/120hz= 8,33ms
1000ms/240hz= 4,16ms
1000ms/360hz=2,77ms
Look at pairs of vertical bars , Pair with number 20.8 they should have a visible gap between them, pair with numer 16.7 should touch edge-to-edge. You look at the first pair that touches, looking from right to left. Whichever pair touches first corresponds to the MPRT value.
Mathematical operations can be performed in a similar manner
1000ms /16,66ms = 60hz
1000ms / 8,33ms= 120hz
1000ms / 4,16ms =240hz
1000ms / 2,77ms = 360hz
Pulsar mode has a duty cycle of 25%, so you have to multiply/divide by 4 to get the equivalent of the MPRT sample and hold.
120hz + Pulsar = 120hz x 4= 480hz
The length of one frame In Pulsar Mode. MPRT value.
1000ms/480hz = 2,08 ms
So in the UFO TEST MPRT indicator. You should see vertical bars that touches edge-to-edge with about 2ms signed under them
If they touch at 8ms and not 2ms, it means that Pulsar is not working.
ANALOGICALLY
240hz + Pulsar = 240hz x 4= 960hz
The length of one frame In Pulsar Mode. MPRT value.
1000ms/960hz =1,04ms
So in the UFO TEST MPRT indicator. You should see vertical bars that touches edge-to-edge with about 1ms signed under them
If they touch at 4ms and not 1ms, it means that Pulsar is not working.
To sum up, the MPRT indicator test can be used to test the strobe mode of monitors and on this basis, without an oscilloscope, etc., we can check the duty cycle.
We can also test without the strobe. If the value is higher than the calculated value, then the monitor has poor GTG speed.
So the monitor has 400Hz, but these Hz are only on paper because it's physically 240Hz. Just like AOC has been doing lately with IPS displays.