TIER2 extension application while waiting for the previous

Dear Forum members,

Could anyone advise me on the following issue?
I had a TIER 2 visa valid until 14 July 2016. My employer promised a one year extension contract but did not prepare it on time. He issued a 2-monts extension and corresponding CoS valid until 31 August 2016. I submitted TIER 2 extension application on 11 July by post.
Now I was issued a new one year employment contract and new CoS starting from September 1.
The problem is that I have not received a decision on my submitted TIER2 application.
The questions are:
- can I submit for a new TIER2 extension without receiving a decision on the previous one?
- If so, what should I write in the application form in the field "What type of visa or leave to remain do you have?" and "Do you have a biometric residence permit?" I could not find is how to say in the online application form that my previous visa is still in consideration with UKVI. Should I give the information on my old expired BRP?

Many thanks

Can you please update ..Have you applied for your new Visa with new COS when the decision pending and what details have you entered in the form.

I guess OH will have your Password and BRP. than how did you apply