Potential reason for the loss in power over time for the fibers on the power distribution center: This says:

Wide-Key-Slot Mating Sleeves - While this configuration is acceptable for patch cables with FC/PC connectors, for FC/APC applications, we recommend using narrow-key-slot mating sleeves to ensure optimum alignment. Our patch fibers are FC/APC. Additionally the adjustable fiber collimators we purchased (pdf attached) are wide key. They don't sell the collimator as narrow key, but we could potentially request it.