The Bench and Press plugin for NLP

I’ve stalled on my upper body during the Starting Strength NLP, so I did some research and stumbled across the plugin from BBM. Today was the first day incorporating Workout A of the plugin, and it went alright until I did OHP. I did my bench routine first, but when I hit OHPs, my arms were already pretty exhausted, and I could only hit the 8 reps once at an RPE 10. Then 7 reps at RPE 10, then 6 at RPE 10, and 5 at RPE 10.

I did the calculation for what my weight should’ve been based on my last 3x5 OHP, but since I was doing this directly after benches, blah. I’m also not used to 8 reps, coming from SS. Is this normal? Will I become more acclimated to doing OHP after benches? Or to the increase in reps per set?

Would appreciate any thoughts on the matter. Already feel pretty defeated from having stalled on my upper body with SS for so long, and then trying this to remedy that problem only to fail the routine.