RLMT details check stage

[gupta_ust]

Hi Experts,

My friend has received an Unrestricted COS for Tier 2(G).
Queries are:

1) I know while issuing a COS employer has to enter details of RLMT like Advert details etc. At what stage UKBA validates these details? At the time when sponsor issues certificate or when a person applies?
In simple words, my friend confirmed that salary details, Job Code etc are all in place. Does that mean all is well or it can be rejected because employer did not conduct RLMT properly?

2) Does it make a difference if COS is issued from "B" rated sponsor rather than "A" rated? I know "B" rated cannot certify for maintenance..any other difference?

[gupta_ust]

Any comments please experts?