Hey Slow..I'm here backing you up.

The only thing to keep in mind with a trans flush is if you are having problems with the trans, then a flush isn't typically going to help it.

Dark fluid is normal after 70K miles. It's not uncommon for it to smell a little cooked and be off color. 70K miles isn't freshly changed fluid.

If you want to flush, I say do it. However ensure that somewhere in the process the filter is changed. Flush doesn't automatically mean filter change.