Tier 1 (General) 2nd extension previous address queries

Hello,

I am applying for a 2nd extension. Although my current visa is expiring next year, I am applying for an extension now, just to save myself from the new fees w.e.f April-2014. Is this fine?

I have few more queries regarding the same application

1. Do I need to justify the reason behind early extension (to save myself from new visa fees) in my covering letter as the gap between my application and the current visa expiry is more than a year? I think it won't affect my ILR application as it will fall between now and my 2nd extension expiry.
2. Do i need to provide the sponsorship letter for dependants?
3. The older version of application form needed you to fill up all previous addresses in the last five years but the new application form (version 10/13) just asks about 1 previous address. Do I need to attach an extra sheet providing details of all my previous addresses in the last five years or is this version of form really just asking for (only) 1 previous address?

Thanks in advance!