Transmitter power and optical loss budget

The specifications for various optical interfaces show a maximum and
minimum transmitter power, differing by about 6-8dB. Are these supposed
to represent variations in the actual transmitted power of new kit or
are do they allow for degradation as the transmitter ages?

What I'm trying to work out is whether a working link, whose nominal
loss exceeds the minimum loss budget, would be likely ..
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Tags: Telecom Cisco technology fiber optic