Thanks, we actually talked about you yesterday
This is where a few of our experiences differ from what you wrote. There was a SD on a YQR YYZ flight which did what you posted, but it's a datapoint that isn't normal for us.
1) J service, Y BOB, and then back to J about oh I dunno, 3-4 times to keep the J passengers served.
The issue though is that it's not what we're seeing. The majority of mine (and other FTers on here)'s experience is a complete abandonment of the J cabin after the meals and drinks are served once. The SD goes back to Y after the initial meals/drinks are served and disappears until BOB is done, which from what was told to me is SOP. (obviously I will divert to your info on what is SOP).
Nonetheless, this is overwhelming what i'm seeing, and I spend a lot of time on E90s. Last night the discussion that was had was the different experiences that we as pax get versus what is shared by you when it comes to what you do onboard. FWIW, and you know as well as others that i'm an AC lover, but in this case there is a material change based on service received because of this 1:50 service. SD's simply are, for the most part, ignoring the J cabin, and so this 1:50 change impacts who? J pax (the most)
Diligent SD's are noticed and I do write in about them, especially on a E90, but it appears to me (respectfully of course) that the majority of SD's abandon J after the initial service and go to Y.
I know i'm a dick for picking on this, but let's say YOW YYZ, it's even more apparent because like Cow says, there isn't enough time for the SD to replenish say drinks after the first round. On a SEA YYZ it's less apparent because the flight is longer but Ben and I had the discussions where he didn't think there would be a change in the quality of service received, and I respectfully (privately) and now in public would say I disagree.