Fmc transfert on 737 NG

[Kgavionics]

Hi
A question for 737 pilots
I know that when pilot enter data to #1 cdu, the active fmc will
Synchronize the data automatically to the cdu#2.i'm wondering
What's the purpose to transfer panel located on the overhead panel.

[B737900er]

For times when the FMC isn't being nice.

[RAT 5]

Do you have 1 or 2 FMC's?

[Kgavionics]

2 Fmc's

I'm asking this question, because i was in737-800 cockpit and i noticed that the copilot is was always touching the Fmc transfer button, despite the 2 FMC were all right.

[STBYRUD]

He was diddling with the FMC transfer switch? I could imagine that was the EFIS transfer switch to copy over minimums to the opposite side, but there is no reason to switch from one FMC to another in normal operation, that switch is used only to switch to the good FMC in case one fails....