That doesn't look good really then 10W, surely NATS should pick that up and address the violations through the UCE scheme? The only other excuse I can think for bad results is how often are Manch using their hourly slot extra tolerances (assuming they have them)? I remember that when I did famil at Gatwick, we could depart 2 an hour at +20 and 2 at +15 rather than the usual +10, I expect Manch has similar? Would the figures be able to show these extra allowed tolerances too?
Having stated earlier, being on the rough end of non-adherence isn't very pleasant and a practice that may well need nipping before it becomes too familiar.