Question about SFP and reliability of reported line loss

[Prototyp_V1.0]

Hi.

Have a pair of managed switches with a fiber pair. The repported line loss in dB by the web interface of the switches - is that number somehow accurate? Or is the accuracy very dependent on manufacturer/model of each network unit or SFP ?

Here is the actual information from each switch web interface (the two SFP's that sees each other)

SFP Details
  Port type is small form-factor pluggable (SFP). Module is inserted.
  Type is CISCO-FIBERWORKS SFP-100B-ZX-C A, 1550 nm, connector LC.
  Serial number:      <filter>
  Capabilities:       Ethernet 100BASE-LX  SONET OC-3 LR-1
  Media type support: 9um SM          80 km
  TX power is 706.4 uW (-1.5 dBm), RX power is 4.7 uW (-23.3 dBm).
  Measured lineloss on rx is 20.3 dB, lineloss on tx is 21.8 dB.
  Module voltage is 3.2736 V, module temperature is 47.875 deg. Celsius.

SFP Details
  Port type is small form-factor pluggable (SFP). Module is inserted.
  Type is ABB 500SSM80 R0001, 1550 nm, connector LC.
  Serial number:      <filter>.
  Capabilities:       Ethernet 100BASE-LX  SONET OC-3 IR-1
  Media type support: 9um SM          80 km
  TX power is 504.0 uW (-3.0 dBm), RX power is 4.5 uW (-23.5 dBm).
  Measured lineloss on rx is 22.1 dB, lineloss on tx is 20.3 dB.
  Receive signal quality is 10.3 dB; Alarm not enabled, warning not enabled.
  Module voltage is 3.2600 V, module temperature is 38.0 deg. Celsius.

In this specific case, the repported line loss are 20.3dB and 22.1/21.8 dB and there is two different brands of SFP talking to each other.