Average or low pass over this timespan.
Means, you get an average output over the last 10 seconds.
The percent value is the allowed deviation from the current filtered value.

Try this filters out, this is self explained.

if you use aquasuite for watercooling, you shouldn't bother with CPU temperature at all to be honest.

for aircooling, it still takes some time to get the fin stack toasty hot, depending on what cooler you use. If you get an averaging or low pass filter with 30s timespan you should be good to go.

From what i see, with the same timespan :
Averaging will give constant, slow temperature variations with CPU load (spikes will cause your fans to spin up and down but a lot slower than with direct CPU temp control)
Low pass filter will in effect erase the short spikes of temperature and only care about baseline temperature increase. it is a lot more stable if you care about sound nuisance.

How the function mathematically works internally doesn't really matter. Just chose the function that suits better what you try to achieve