Yeah, but that's just the top sets. There is a second round of bench that day too working up to 80%x2x4, plus 85% generally feels a bit heavier by week 5 because you are lifting in this range 3x a week, plus a fourth lighter day.
Wednesdays are the big volume days in this program, eg week 5 day 3 is 50% 5x1, 60% 5x1, 70% 4x2, 80% 3x2, 85% 2x2, 90% 1x2, 85% 2x2, 80% 3x2, 75% 4x1, 70% 5x1, 60% 6x1, 50% 7x1, followed by a shit load of accessory.
Sheiko always looks much easier on paper then it feels, particularly as you get deeper into a long cycle. It's designed to work that way. You can produce a suprising amount of soreness from 4x a week submaximal benching.