Allowedmeasbandwidth: How close can be this to channelbandwidth??

[eta004]

I need to configure a scanner to scan many ARFCNs ..
I have the SIB5 messages having different EARFCNS with "allowedmeasbandwidth " as the sole clue to channel bandwidth.
But I have observed some operators are using full channel bandwidth for allowedmeasbandwidth and some cases they use only 6RBs!

1) How much likely is the "allowedmeasbandwidth " same as Channel bandwidth?
2) Why " allowedmeasbandwidth " varies in different SIB messages?

[wolverine]

The MIB has the only true indication of the actual channel bandwidth.

[ls2398]

With some features that usually involve attempting to reduce RS inter-cell interference the vendors make you set SIB5 to mbw6. E******* does this for lean carrier I believe and Huawei does it for Breathing Pilot. It's just meant to give the maximum RBs a UE can measure, not designed to give a true indication of channel bandwidth, as stated you need the MIB for that.