Error retrieving dials from several cisco switches

Dear Support,

I have a list of 50 switches Cisco Catalyst from the same model (series 2900) with the same IOS version, and some of them gives me info:

Two of them gives me CPU, memory and Backplane
Some of them gives the CPU and memory
Other devices only CPU
A few only the backplane utilization

For Memory dial, some times uses .1.3.6.1.2.1.25.5.1.1.2 OID (MemoryUtilization) and for other ones uses (.1.3.6.1.4.1.9.9.48.1.1.1.5.1*100)/(.1.3.6.1.4.1.9.9.48.1.1.1.5.1+.1.3.6.1.4.1.9.9.48.1.1.1.6.1) (CiscoMemoryUtilization)

For the CPU I used .1.3.6.1.4.1.9.2.1.58.0 OID (CPU Usage (5 mins avg))

I have rediscover all switches one by one several times, and stills the same. Why OPM6 don't gives me the same info for equals devices?

Thanks.

Daniel Lopez.