Goldtarget I was once taught that the ground balance is like a a ground mineralisation discriminator.
The results your getting now though will vary depending on the ground and make sure you do your tests because you
can mask targets out especially in more mineralised soil if your running in the positive.
What you have discovered does work but each machine is different.
Sometimes a slight change is all that's needed.
There are guys who use an XP Deus running it in manual for the very same reason which can become a balancing act.
The other thing is if in auto ground tracking and your looking for very small gold you simply don't know if your ground tracking is tracking
out the target and for this reason it is not an issue with a manual ground balance detector like a gold bug 2.
There is a big gap in your tracking which the machine has a reading of 75 and you have changed it to 35. Are you using a DD?
One great area to use this little trick is in tot lots and watch the deep $2 coins pop out
In my opinion there are 2 important factors in a detector and its not bells and whistles.
You have discovered one of them. The other is unmasking good targets among iron and not many machines can do this.
Once you have both then new ground is automatically opened up because good targets close to iron that was masked
out and discriminated out by previous machines are detectable by faster and more capable machines.