I tested something: In [Pic1] I have ranged the mortar to 900m. In [Pic2] you can see that the flight time is around 35.3 SEC for that and delta t for 100m is 0.1 SEC. Now in picture [Pic3] you can see that the automatic fuse time is 34.3s and finally in [Pic4] you can see the final altitude of the flare of about 100m.

I might misunderstand something but I thought a flare altitude of 100m would require a fuse time of about 35.2 SEC then and a flare with the fuse time of 34.3 SEC would have a much higher altitude. Looking it at that way the numbers seem to be inconsistent or I overlooked something.

I labeled it more as Feedback as one can easily work around it. Just first look at the automatic fuse time and height correct it with that number.