I've been relegated to the trainer for the past 8 weeks focusing mainly on L4 efforts via 3x20's and 4x15's. Looking at my power distribution chart for those 8 weeks I see a definite even plateau in 3 bins (10 watt bins) and then a significant drop in the fourth bin. Could this be a close approx (within 10 watts or so) of my FTP even though I've done no efforts longer than 20 minutes in that time frame? I plan on testing outdoors in the next week or two but wanted to use my chart numbers to give me something to shoot for.