If you think your warmups are taking a long time at 135, wait until you're squatting 4 plates, lol.
I'm confused as to what you think the "recommended" warmup protocol is that apparently takes longer than this.Example from last time: 5x45, 5x65, 5x95, then 3x5x135 for the work.
If I was warming up to 135 I would probably do 5x45, 1x95, 1x115, then the work sets. Are you resting between warmup sets? Don't. Just add the plates and squat. Just rest a bit before the worksets.