Tier 2 Extension - Minimum funds requirement, CoS x2

Hi friends,
A) Is there a minimum fund requirement (in the last 90 days), for Tier 2 extension- for main applicant and dependants ? What are the documents required to show maintenance ?
B) When there are 2 CoS issued from different sponsors, is it necessary to withdraw one CoS before submitting the application for extension ?
Many thanks !

1. If the extension is with the same employer and same SOC code, you dont have to provide the maintenance documents.

2. Yes. You cannot have 2 CoS assigned to you at any point of time.

Thanks moonlight55
Much appreciated