1) if you were working out with SS techniques, you wouldn't have a 315 bench to a 200 squat.
2) the Texas method is not for people in their 40s. Do not use it. Perhaps run old man Texas method. Before considering that, however,
3) with a 200 lb squat, it's pretty dang unlikely you are an intermediate lifter (though you may be on your bench and press). If 200 lb squats are hurting your knees such that you are not squatting much, you're probably squatting wrong. Therefore,
4) get a coach. startingstrengthonlinecoaching.com or SSCA : Coaching
5) stop running until you've finished your LP