SFP Tx power - is it static or dynamic?

As many of you know, SFP's have their Tx signal powers specified as a range. For example:

Minimum: -6 dB

Maximum: 1 dB

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I have two identical SFPs, which currently run at very different Tx power and Current.

-1.51 dBm vs -3.46 dBm

37.00 mA vs 21.32 mA

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Since the one with -1.51 dBm also has much worse Rx signal than the one with -3.46 dBm, I started wondering, if (some) SPFs dynamically re-tune their Tx power based on Rx measurement or some other parameter.

Or is it just a coincidence and it's just a lottery, how powerful SFP you get? Anyone know for sure or can maybe link to some in-depth article?