It sort of tells us we shouldn't repeat verbatim from the police's statements many of which were written in hindsight and not accurate.
An effort should be made to figure out what they actually meant. Also to make sure that there is not evidence that establishes they were wrong.
Bews thought he might have seen movement in the master bedroom window so obviously the light was on. If It was off he would not have been able to think he saw anything. Mildinhall had a better look than Collins and Delgado because he was stationed at the front of the house so had reason to remember what he saw and was able to describe the windows he saw. He says the light was on in the bedroom but not any other rooms.
Collins and Delgado said a light above the main door was on. Maybe they misrecalled the bedroom as being above the main door, maybe they saw light from the hall entering the sewing room, maybe they meant the porch light. Unless they meant the bedroom but did a poor job of conveying it they made a mistake and failed to note the bedroom light had been on.
The statements of others especially someone who described the 3 upper windows with so much detail as to noting the curtain situation is more credible than them in that respect.
In contrast, their observations about the kitchen side would be more reliable than people not stationed on that side. They were able to describe the certain situation in detail showing they looked carefully, indeed they stared at the those windows for hours so such would be expected.
Their frame of reference has to be considered in addition to trying to figure out what they mean. If there is something they can't have witnessed then you look for who supposedly told them the detail and then go try to see where that person got it from and try to trace back to a source. This is what we always should do with evaluating claims.