Todd does have a great point. Squat/deadlift combos are extremely tough, BUT it may indeed be what you need to do......turn up the intensity and do the tough stuff!!
We must try to avoid absolutes.....e.g. "You cannot get maximum results by squatting and deadlifting in the same day." There are a TON of training protocols that work. I know many powerlifters squat and deadlift in the same session and because of it they are extremely strong and power (they also carry a large amount of
muscle mass around with them as a result of it too). There was a recent article on another website that stated something like, "20% of your actions are responsible for 80% of your results". Now if we agree that
heavy compound movements like squats, deads, chins, rows, bench etc are responsible for most of your strength progress why not focus your time on them instead of going over to the cable crossover machine?
I applaud you in your efforts. Squat & Deadlift away.