How are you determining your loading? By percents? Of What?
I was wondering if it might be time to start moving away from strict 5x5. My suggestion to try would be to work toward 3 working sets, and space them closer together, then doing fewer reps on the heavier warm-up sets. The weights you reported today seemed really "spaced-out" to me. If the top set is around 95% of 1RM, then really only the 2 top sets are giving you much in the way of strength training, but the lower sets are likely still contributing to fatigue.
Here's what you posted: 5x135, 5x185, 5x225, 5x255, 5x305
Here's what I'd suggest trying: 5x135, 2x185, 2x225, 1x 255, 1x175, 5x185, 5x195, 5x205
Or maybe: 5x135, 2x185, 2x225, 1x255, 5x275, 5x290, 5x305
Or even: 5x135, 2x185, 2x225, 1x255, 1x275, 5x285,5x285, 5x285 (or 280, or 290 on the last 3 sets or whatever)
My thought is to spend more of your available total energy on the sets that add more strength.
I'm nowhere near my 95% 1RM. I didn't base it off of a percentage, but when I decided to do the ramping of DL sets after re-visiting both practical programming and strong lifts, I went back to my max-ot warmups, where you went up 50,40,30...However I'm obviously not doing the same number of reps during the warmups. Now that the numbers are going up, I need to either add more warmup sets, or start with a higher weight.
Perhaps on Saturday I try 5x165, 5x225, 5x265, 5x295, 5x315