Hoping someone can help...

I operate a small door company and we're having a problem with raised
panel end grains.

We have a very expensive shape and sand machine....all set up correctly
etc...

No matter what setups I use when the panels are stained....the end
grains come out very dark and splotchy.

I know the big companies sand end grain effectively. What are some tips
everyone has? I've read some of the other posts but people speak in
generalities.

I need specific tips....any help appreciated.