Maybe there are transceivers with auto-power adjustment, but definitely not all of them. Maybe you can mention some specific model which does that? Never seen that before..The SFP's will automatically increase/decrease power as needed. There's no minimum distance for a fiber cable. Maximum limitations are provided as there is loss / fade over long cable runs.
You only have to use attenuators when you use transceivers for a distance of couple meters. S-3553LC20D range is 20 kilometers, for example, if you use them to interconnect two devices with range 10km, attenuators is not necessary.If support say attenuators are required is the datasheet incorrect?