calculate how low your targets are from the ground turn make sure RHM is on for the altimeter radar if its off and refuses to switch fly low and make sure your navigation is switch on nav.
you can go below the STD by using valb down to 30m about 100 feet. I usually put in tak in
910033, 32, or 34 then tak in 922 this gives me the best results. I notice online the BK90s do not calculate for wind this can make the drag chute bomblets go off course.
lastly when setting a new waypoint close make sure terr nav has a 5 on the 5th digit on akt mode,if its 1 then its useless. i had a bug happened with terrnav grab a new plane or try turning it off and back on.