Bending the ankles also should be accompanied by bending the knees (five dollars please ).
You want to have contact with the tongue of the boot to apply pressure to the front of the ski, but you also want to maintain your COM over your feet, not over your toes or further forward. If your hips are in fact over your toes, then you probably arent' bending the knees adequately to keep your COM further aft. Your knees could be over your the balls of your feet while your hips are over your heels and your torso is slightly forward so your shoulders are over your arches. These position references are kind of arbitrary but are meant to say that your knees lead, your hips follow and your shoulders are somewhere in between resulting in a COM over, roughly, the center of your foot.
Pressure on the tails generally isn't desireable although less pressure on the tips resulting in pressure more centered on the ski is fine such as when you are releasing the ski from a turn.
When your hips are over your toes, you are in a very upright stance and presumably your upper body is projecting even further down the slope, not leaning back. If this analysis is correct, then your COM is well ahead of your toes. This will make a heel release quite likely if your skis hit something that slows them down and your upper body continues forward. Skiing in crud requires that you keep your COM over your feet and when you hit snow that will slow your skis, that you resist the forces that want to pitch your body forward. 'Prepare to take the blow' by tightening your core and letting your body mass drive your skis through the crud.
I'm going to assume that the bindings are set properly and that adjusting your technique for crud will help reduce heel releases.