BF GAS and IMV OSEM motion does not match, even though two sensors monitors mechanically same at lower frequencies than the resonant frequency of IRM V which is more than 10 Hz.

BF GAS and IMV OSEM differs by

BS: BF GAS response is bigger by 2.3 times than IMV OSEMs.
PR2: BF GAS response is bigger by 3.3 times than IMV OSEMs.
PR3: To be investigated
PRM: almost the same (0.3 dB difference)
SR2: almost the same (0.4 dB difference)