You always perform Bench and Incline bench before your presses if memory serves me correctly and at relatively higher volume for HST. Naturally your OHP will not climb as steadily due to the amount of fatigue those muscles have already endured during the session. You may also notice the same issue with BOR as I believe you do your pullups and chins prior to that as well. If you did OHP first for example I bet you would be suprised at how much you could do, but I don't expect you to do that. Doing 140 x 5 after your chest work is nothing to be ashamed of. Try deloading as grunt has mentioned or even switch to push press if you want to increase poundages. Good luck