IMHO this also works the other way around in soft footing. I am not familiar with all the theories and have no opinion on them, but the way I understand it, bringing the toe closer will make the lever smaller and allow it to sink more, increasing the angle. Bringing the heel closer will make that lever shorter, allow it to sink deeper and decrease the angle. So my understanding is that in soft footing bringing the toe closer, all other things unchanged, will increase the angle and load the suspensory a bit more. Bringing the heel closer, all other things unchanged, will decrease the angle and load the tendon a bit more. Just some thoughts to help with the cases where there's nothing more you can do for the HPA with the horse standing on concrete.