5 Year calculation ILR -PSW to TIER 1 GENERAL

[etelsa]

Anyone out there to help please?

Given the following:

PSW (International Graduate Scheme): 28 April 2008 to 28 April 2009 (I applied myself at Croydon HO)
Tier 1 General: 27th May 09 to 27 May 2012 (I applied by post on 26th March 2009)
Tier 1 General Extension: Valid until 27th May 2014 ( I went to the HO Croydon on 15 March 2012)

Should I apply end of March 2014 or end of April 2014?

I know that PSW don't qualify for the 5Y, but then how about that month between 28 April 2009 and 27 May 09 (Does it not count on my 5 years qualifying period) when I was waiting for my passport to be return from the HO


Many thanks