Setting aside the on-DSP stacking (usually called as 3D-NR), here we are talking about setting image sensor's exposure time...
Please realize that the tool cannot set the exposure time beyond what the max value image sensor can be set.
These image sensor SoC, especially designed for security cam, video cam etc. can only operate in "streaming mode".
That is, images are continuously being acquired and read out. I.e., itself cannot support "one-shot readout mode" as what is used in
a DSLR or mirrorless. The latter is in a different class of imaging devices.
In reading the full datasheet, it is clear the former can have the max. exposure time on per-frame basis of typically 0.5 second (or in some devices, 2 seconds.)
It is the penalty to pay once you realized that the purpose of such sensors.
Naturally, an obvious question... how come the same image sensor used in an astroCMOS imager does not have such per-frame max. exposure time limitation?
Answer is that astroimager mfrs spent their R&D time to perform some beyond-spec (nicely worded as undocumented) operations thru a combination of hardware/firmware tricks.
That's how they turn a niche market device with (often times) less hardware, at least, no camera DSP into a more expensive/with some niche capabilities/"less capable as a self-contained camera".
P.S. examples of niche capabilities: long exp time, low dark current/low power operations most of time, etc.
If you believe the security camera seller said "PQtools can extend the exposure time", you might just as well spend your hard earned money to buy a lotto and use the winning money to buy a right imaging device.