I try to run my lunch run at the same "effort" pretty much every day. The time can range from 26 minutes the day after a long race to under 21 minutes on a fast day. I've only been running this particular version of the course since I moved back to our Methuen office. So, I've only got data from about 15 months. On Monday I ran my first sub 19, despite the wind and cold. I felt good from the start and although it wasn't easy, I would still call it comfortably hard.
Here is my CR progression for the 3m multiple loop course over the last 2 months
10-13-10 = 19:35
10-27-10 = 19:12
12-06-10 = 18:57